Apparatus and system for roasting coffee beans

ABSTRACT

An apparatus for roasting coffee beans comprises a roasting chamber for containing coffee beans. The roasting chamber is positioned within a resonant cavity of a waveguide. A microwave emitter produces microwave energy within the waveguide with one or more stable high intensity microwave regions within the roasting chamber to heat the coffee beans in the roasting chamber to a temperature sufficient to roast the coffee beans. A device configured to move the coffee beans within the one or more high intensity microwave regions is coupled to the roasting chamber.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation-in-part of and claims priorityto pending U.S. patent application Ser. No. 13/794,519, filed on Mar.11, 2013, by Stephen C. Jacobsen and John McCullough, the entirety ofwhich is incorporated by this reference.

FIELD OF THE INVENTION

The present invention relates to novel devices and methods for roastingbeans, such as coffee beans, using microwave energy.

BACKGROUND OF THE INVENTION

Roasting coffee transforms the chemical and physical properties of greencoffee beans into roasted coffee products. The roasting process is whatproduces the characteristic flavor of coffee by causing the green coffeebeans to change in taste. Unroasted beans contain similar if not higherlevels of acids, protein, sugars and caffeine as those that have beenroasted, but lack the taste of roasted coffee beans due to the Maillardand other chemical reactions that occur during roasting. The Maillardreaction is a chemical reaction between amino acids and reducing sugarsthat gives browned food its desirable flavor.

The vast majority of coffee is roasted commercially on a large scale,but small-scale commercial roasting has grown significantly with thetrend toward “single-origin” coffees served at specialty shops. Somecoffee drinkers even roast coffee at home as a hobby in order to bothexperiment with the flavor profile of the beans and ensure the freshestpossible roast.

The coffee-roasting process follows coffee processing and precedescoffee brewing. It consists essentially of sorting, roasting, cooling,and packaging but can also include grinding in larger-scale roastinghouses. In larger operations, bags of green coffee beans are hand- ormachine-opened, dumped into a hopper, and screened to remove debris. Thegreen beans are then weighed and transferred by belt or pneumaticconveyor to storage hoppers. From the storage hoppers, the green beansare conveyed to the roaster. Initially, the process is endothermic(absorbing heat), but at around 175° C. (347° F.) it becomes exothermic(giving off heat). For the roaster, because the beans are heatingthemselves, an adjustment of the roaster's heat source might berequired. At the end of the roasting cycle, the roasted beans are dumpedfrom the roasting chamber and air-cooled with a draft inducer.

In Vietnam coffee is often coated with oil (traditionally clarifiedbutter) and a small amount of sugar prior to roasting to produce a“butter roast”. The roasting process results in an additionalcaramelized coating on the beans.

The most common roasting machines are of two basic types: drum and hotair. There are also packed-bed, tangential and centrifugal roasters.Roasters can operate in either batch or continuous modes. Drum roastingmachines consist of horizontal rotating drums that tumble the greencoffee beans in a heated environment. The heat source can be supplied bynatural gas, liquefied petroleum gas (LPG), electricity or wood. Themost common employ indirectly heated drums where the heat source isunder the drum. Direct-fired roasters are roasters in which a flamecontacts the beans inside the drum. Fluid Bed or hot air roasters forceheated air through a screen or perforated plate under the coffee beanswith sufficient force to lift the beans. Heat is transferred to thebeans as they tumble and circulate within this fluidized bed.

Various attempts in the art have been made to roast coffee beans usingmicrowave energy. For example, U.S. Pat. No. 4,326,114 discloses amicrowave oven incorporated in a coffee bean roasting system andincludes a rotatable microwave transparent tube or drum positionedwithin the same and at an angle to the horizontal, through which coffeebeans are introduced at an upper end and flow in continuous agitation tothe lower end while being subjected to microwave fields within the oven.At the lower end of the oven a separate section is preferably providedfor subjecting the coffee beans to selective treatment during the finalstages of the roasting process. In one form utilizing a unitarystructure the separate section is provided by a conductive septum, whichseparates the oven into sections in which the power level is different.In the last section the power level is adjusted to control the finalcritical phase of the roasting process. The oven terminates into acooling and quenching chamber from which the beans are delivered througha microwave trap to a further cooling stage to rapidly reduce theirtemperature to well below roasting.

Other devices have been disclosed for providing a device for roastingcoffee beans in a conventional microwave oven. Such devices aredisclosed in U.S. Pat. Nos. 7,235,764 and 6,436,457. PCT ApplicationPub. No. WO 2008/087622 A2 discloses an open roasting pan for insertinginto a common or microwave based home oven for roasting coffee beans.The roasting, however, takes about 20 to 25 minutes.

A number of names have been commonly used to identify the variousdegrees of roast, such as City Roast and French Roast, based on theinternal bean temperatures found during roasting. Often, a recipe knownas a “roast profile” is followed to obtain certain flavorcharacteristics of the roasted coffee beans. A number of factors canaffect the best profile to use, such as the coffee bean's origin,variety, processing method, moisture content, bean density and/ordesired flavor characteristics. A roast profile can be presented as agraph showing time on one axis and temperature on the other, which canbe recorded manually or using computer software and data loggers linkedto temperature probes inside various parts of the roaster.

As the coffee beans absorb heat during roasting, the color shifts toyellow and then to increasingly darker shades of brown. During the laterstages of roasting, oils appear on the surface of the bean. The roastwill continue to darken until it is removed from the heat source. Coffeealso darkens as it ages, making color alone a poor roast determinant.Most roasters use a combination of temperature, smell, color, and soundto monitor the roasting process. The most popular, but probably theleast accurate, method of determining the degree of roast, however, isto judge the bean's color by eye. To obtain more accurate roasts,devices that quantitatively measure the roast have also been developed.For example, Agtron, Inc. of Reno, Nev. sells coffee roast analyzersthat include spectrophotometers to analyze the degree of roast of groundand whole bean coffee. The Agtron analyzers use a narrow band ofnear-infrared energy to evaluate the coffee roast both as a whole beanand in a ground form.

Sound is a good indicator of temperature during roasting. There are twotemperature thresholds called “cracks” that roasters listen for. Atapproximately 196° C. (385° F.), the coffee will emit a cracking orroasting sound. This point is referred to as “first crack,” marking thebeginnings of a “light roast.” At first crack, a large amount of thecoffee's moisture has been evaporated and the beans will increase insize. When the coffee reaches approximately 224° C. (435° F.), it emitsa “second crack,” this sound represents the structure of the coffeestarting to collapse. If the roast is allowed to progress too muchfurther, the coffee will fully carbonize and eventually combust.

The following table sets forth various common roasts based on beantemperature and a description of the resulting roast at thattemperature.

Green Beans - 22° C. (72° F.) Drying Phase - 165° C. (329° F.) Greencoffee as it arrives at the dock. During the drying phase the beans Theycan be stored for approximately are undergoing an endothermic 12-18months in a climate-controlled process until their moisture environmentbefore quality loss is content is evaporated, signifying noticeable.first crack. Cinnamon Roast - 196° C. (385° F.) Light Roast - 205° C.(401° F.) A very light roast level that is Moderate light brown, butstill immediately at first crack. Sweetness mottled in appearance. Apreferred is underdeveloped, with prominent roast for some specialtyroasters toasted grain, grassy flavors, and highlights origincharacteristics as sharp acidity prominent. well as complex acidity.American Roast - 210° C. (410° F.) City Roast - 219° C. (426° F.) Mediumlight brown, developed Medium brown, common for most during first crack.Acidity is slightly specialty coffee. Good for tasting muted, but origincharacter is still origin character, although roast preserved. characteris noticeable. Full City Roast - 225° C. (437° F.) Vienna Roast - 230°C. (446° F.) Medium dark brown with occasional Moderate dark brown withlight oil sheen, roast character is surface oil, more bittersweet,prominent. At the beginning of caramel flavor, and acidity muted. secondcrack. In the middle of second crack. Any origin characteristics havebecome eclipsed by roast at this level. French Roast - 240° C. (464° F.)Italian Roast - 245° C. (473° F.) Dark brown, shiny with oil, burntNearly black and shiny, burnt tones undertones, acidity diminished. Atbecome more distinct, acidity the end of second crack. Roast nearlyeliminated, thin body. character is dominant; none of the inherent aromaor flavors of the coffee remain.

As noted in the table above, green coffee beans can be stored forapproximately 12-18 months before quality loss is noticeable. However,for coffee beans to be considered part of the “current crop,” thestorage time cannot exceed one year. If the green coffee remains instorage for longer than a year, it is considered old crop, and is lessvaluable because of its drier state. Once the coffee is roasted,however, the shelf life is significantly reduced.

After roasting, the coffee beans contain carbon dioxide that is emittedfrom the beans over time. For dark-roasted coffee, the beans can emit upto 10 liters per kilogram of coffee. The roasted coffee beans rapidlyemit carbon dioxide over the first few days after roasting, then moregradually over the remainder of what is referred to as the degassingperiod. The carbon dioxide in the roasted coffee beans forms a barrieragainst oxidation, which is part of staling that degrades quality byaltering the roasted coffee bean's essential oils and aromaticcomponents. Exposure to moisture, high temperature and light aftercoffee beans have been roasted are also known to detrimentally affectthe quality of the roasted coffee beans by accelerating oxidation of theroasted coffee beans and degrading their aroma. Thus, it is desirable tolimit the time of storage of roasted coffee beans to obtain the bestquality coffee.

As noted above, retention of carbon dioxide in the beans is desirablefor a number of reasons. In addition, for preparing espresso, the carbondioxide in the roasted coffee beans creates the highly desirable “crème”(the silky foam that forms on the top of the brewed coffee). Thus, it isdesirable to utilize freshly roasted coffee beans that have retainedsignificant amounts of carbon dioxide to produce the most desirablebrewed coffee products.

Conventional coffee bean roasting methods, including those that haveattempted to use microwave energy, have various disadvantages. Onecommon disadvantage to all such roasting methods is that they take toomuch time to produce roasted coffee beans on demand. In addition, suchroasting methods often require specialized equipment that is configuredto prepare large quantities of roasted coffee beans, which may notremain fresh if not used within a few days. The methods used previouslycan also result in non-uniform heating of the roasted coffee beans,resulting in uneven or incomplete roasting of some of the beans.

Although standard multi-mode kitchen microwave devices have been used inthe art for roasting coffee beans, the long processing times can resultin burning of some of the coffee beans while other coffee beans in thesame batch are under roasted. Non-uniform roasting will affect the tasteand aroma characteristics of the resulting coffee brewed form suchbeans. As a result, the processing times, costs of production and lossesin efficiency and quality of end product are compromised.

Improvements in the prior art methods have been subject to certainconstraints. For example, the prior art specifically teaches thatroasted coffee bean results are sensitive to the rate of rise of thetemperature of the coffee beans during roasting. For roasting coffeebeans in a roasting pan, the prior art teaches preheating a roasting panto about 260° C. (500° F.), which is extremely hot and can result insever burns if not handled correctly. At this temperature, the roastingtakes about 8-10 minutes, with the first crack at approximately 5minutes. After roasting, the beans must be quickly cooled to preventfurther internal roasting as a result of heat that is retained in thebeans from the roasting process.

Thus, there exists a need in the art to provide a method, system anddevice for improving coffee roasting. The various aspects andembodiments of the present invention, as described below, representnovel improvements on the above devices and methods of the prior art.

SUMMARY OF THE INVENTION

The present invention relates to improved systems and devices forproducing roasted beans, grains or seeds rapidly to provide variousimprovements over conventional production systems and methods. Variousaspects of the invention can be used to produce roasted beans morerapidly and having greater control over roasting quality and type,without burning the beans, despite the significantly higher intensity ofmicrowave energy used.

In one aspect, the present invention relates to a microwave device forroasting coffee beans. In one embodiment, the microwave device comprisesa roasting chamber for containing beans; a microwave emitter configuredto produce microwave energy within the roasting chamber; a microwaveenergy focusing device configured to generate focused microwave energywithin the roasting chamber and creating a stable microwave highintensity microwave region in the roasting chamber; and an air blowerfor causing movement of the beans within the roasting chamber andcausing the beans to move within the roasting chamber. In oneconfiguration, the air blower is configured to move beans in theroasting chamber at a sufficient speed to substantially uniformly heatthe beans. In another configuration, the air blower is configured tocirculate beans within the roasting chamber at a velocity greater than 1revolution per second. The air blower may be any type of air blower, forexample, an axial or propeller fan, a centrifugal or radial fan, aturbine, an air compressor, cross-flow fans, combinations of such airblowers, and the like. The moving beans are subjected to focusedmicrowave energy within the roasting chamber, sufficient to moreuniformly heat the beans and cause the beans to roast. Depending on thetime of exposure to the focused microwave energy, the type of roastdesired for the beans can be precisely controlled.

In another aspect, there is provided an apparatus for roasting beanscomprising: a roasting chamber for containing beans; a microwave emitterconfigured to produce microwave energy within the roasting chamber andheat the beans to a roasting temperature; and at least one air blowerdisposed in communication with the roasting chamber for moving beanswithin the roasting chamber. The roasting chamber is at least partiallydisposed within a waveguide for channeling microwave energy into theroasting chamber. In yet another configuration, the roasting chamber issmaller than a wavelength of the microwave.

In another aspect, there is provided an apparatus for roasting beans,comprising: a roasting chamber configured to contain beans; a microwaveemitter configured to produce microwave energy within the roastingchamber and heat the beans; a single-mode resonant microwave applicatorconfigured to generate a stable focused high intensity microwave regionwithin the roasting chamber; and an air blower configured to createairflow within the roasting chamber sufficient to move the beans withinthe roasting chamber.

In another configuration, there is provided an apparatus for roastingbeans, comprising: a roasting chamber for containing beans; a microwaveemitter configured to produce microwave energy within the roastingchamber and heat the beans; a single-mode resonant microwave applicatorconfigured to generate a standing microwave energy field comprising anarray of one or more high intensity microwave regions; and a deviceconfigured to move beans within the high intensity microwave regions. Inone embodiment, the device configured to move beans within the highintensity microwave region comprises a stirring or mixing device withinthe roasting chamber to move the beans within the roasting chamber. Inanother embodiment, the device configured to move beans within the highintensity microwave region comprises a spinning cup within which thebeans are positioned.

In another configuration, an air blower is configured to blow air intothe roasting chamber to remove chaff during the roasting process. Chaffis the brown flaky skin of the bean that comes off the bean during theroasting process.

In another configuration, the air blower is configured to blow air hotair into the roasting chamber during the roasting process to aid in theroasting process and to blow cool or ambient temperature air into theroasting chamber after the roasting process to aid in quickly coolingthe roasted beans. Thus, the air blower may also comprise a heater forheating the airflow to be passed through the roasting chamber.

In another configuration, the present invention also provides a coffeeroasting vending machine, comprising: a bean holding chamber configuredto store and dispense unroasted beans; a roasting chamber comprising aninlet configured to receive unroasted beans from the bean holdingchamber; a microwave emitter configured to produce microwave energywithin the roasting chamber and heat the beans; a single-mode resonantmicrowave applicator configured to generate a stable focused highintensity microwave region within the roasting chamber; a devicedisposed in the roasting chamber for circulating and/or moving the beanswithin the stable focused high intensity microwave region. In anotherconfiguration, the machine is adapted to be activated by a purchasetransaction. In another configuration, the purchase transactioncomprises payment by any one or more of a coin, paper bill, plasticcharge card, or token. In another configuration, the purchasetransaction comprises electronic payment.

In another configuration, the apparatus may also comprise an outletchannel connected to the roasting chamber for discharging roasted beans.In another aspect, the apparatus may also comprise a heater for heatingthe airflow to be passed through the roasting chamber. In anotherconfiguration, the apparatus may comprise a control module forcontrolling the temperature, flow rate, and flow path of the air. Inanother configuration the apparatus may comprise a metering system fordelivering a specified quantity of beans to the roasting chamber.

In one configuration, the high intensity microwave region includes amicrowave energy maxima located within the roasting chamber. In anotherconfiguration, a single high intensity microwave region is locatedwithin the roasting chamber. In another configuration, a plurality ofhigh intensity microwave regions are located within the roastingchamber. In yet another configuration, the high intensity microwaveregion excludes a microwave energy maxima located within the roastingchamber. In another configuration, a plurality of high intensitymicrowave regions are located within the roasting chamber. In yetanother configuration, the high intensity microwave region includes amicrowave energy maxima located within the roasting chamber. In anotherconfiguration, a single high intensity microwave region is locatedwithin the roasting chamber. In another configuration, a plurality ofhigh intensity microwave regions are located within the roastingchamber. In another configuration, the roasting chamber has a diameterthat is greater than the microwave wavelength. In yet anotherconfiguration, the diameter of the roasting chamber is such that beanscirculating within the roasting chamber pass through a microwave energymaxima of two adjacent high intensity microwave regions. In anotherconfiguration, the roasting chamber encompasses a perimeter of twoadjacent high intensity microwave regions that excludes a microwaveenergy maxima.

In one aspect, the device is configured such that the roasting chamberis between two adjacent microwave energy minima nodes. In variousconfigurations, a sidewall of the roasting chamber is positioned suchthat beans at a roasting chamber sidewall pass through a portion of thehigh intensity microwave region wherein the energy intensity is at least50% of the energy maxima, the energy intensity is at least 60% of theenergy maxima, the energy intensity is at least 70% of the energymaxima, the energy intensity is at least 80% of the energy maxima, theenergy intensity is at least 90% of the energy maxima, or the energyintensity is 100% of the energy maxima. In another configuration, thediameter of the roasting chamber is approximately equal to one-halfwavelength and the roasting chamber is positioned such that beans at aroasting chamber sidewall pass through two adjacent high intensitymicrowave regions. In another configuration, the diameter of theroasting chamber is approximately equal to one-half wavelength and theroasting chamber is positioned such that beans at a roasting chambersidewall pass approximately through the energy maxima of two adjacenthigh intensity microwave regions. In another configuration, theapparatus comprises a plurality of anti-node high intensity microwaveregions. In another configuration, the roasting chamber encompasses aplurality of high intensity microwave regions and wherein the blower isconfigured to rapidly move the beans through the high intensitymicrowave regions. In another configuration, the apparatus comprises aplurality of roasting chambers, wherein substantially all of each of theone or more high intensity microwave regions is located within one ofthe plurality of roasting chambers. In another configuration, thesingle-mode resonant microwave applicator is configured to generatemicrowave intensity within the roasting chamber to subject the beans tomicrowave energy sufficient to roast one or more of the beans withinapproximately 13-50 seconds. In another configuration, the devicecomprises two or more microwave energy sources such that the two or moremicrowave energy sources constructively interfere at approximately thesame location within the roasting chamber.

In accordance with one aspect of the invention, the apparatus comprisesan airflow input and an airflow outlet and the air blower causes airflowto pass in the airflow input, through the roasting chamber, and out ofthe airflow outlet. In another aspect, the air blower is configured tocause airflow within the roasting chamber in a horizontal directionsufficient to move beans in a generally horizontal and generallycircular path in the roasting chamber. In another aspect, the apparatuscomprises an air input in the side of the roasting chamber, wherein thehorizontal airflow comprises airflow input into the roasting chamberfrom the side of the roasting chamber at an angle generally tangentialto the roasting chamber. In another aspect, the air blower may be one ormore blowers for creating an airflow pattern within the roasting chamberto thereby move the beans. In one configuration, the roasting chamber isgenerally cylindrical in shape and the air blower is configured to causeairflow within the roasting chamber in an approximately circular pathand move the beans horizontally within the roasting chamber in anapproximately circular path. In another configuration, the air blower isconfigured to cause airflow within the roasting chamber in a verticaldirection, from a lower portion of the roasting chamber upwardly to anupper portion of the roasting chamber. This may include an airflow thatstarts generally horizontally to cause the beans to move in a generallycircular direction within the roasting chamber. The airflow may also beconfigured to form a helical movement path so that it causes the beansto move generally circularly within the roasting chamber and then movesupwardly in a helical or spiral configuration to carry chaff from theroasted beans out of the roasting chamber. In the alternative, two airflow paths could be used with one being more vertical. In anotherconfiguration, the air blower is configured to cause the verticalairflow at a rate sufficient to selectively move chaff from roastedbeans out of the roasting chamber when roasted. In anotherconfiguration, the air blower is configured to create airflow in both avertical direction and a horizontal direction.

In another aspect of the invention, airflow may be directed from twodifferent sources to create a desired movement pattern for beans duringroasting and then to cool the beans after roasting. One pattern may beconfiguration to provide substantially circular airflow of the beansprior to roasting while the other may be configured to cool the beansafter roasting. Alternatively, a single airflow source may be providedto perform both functions.

In accordance with another aspect of the invention, the beans may bemoved within the high intensity microwave region by means of a rotatingroasting chamber, such as a spinning cup, which causes the beans tocirculate with the roasting chamber while they are subjected tomicrowave energy. In one configuration, the spinning cup has sides thatare longitudinally sloping. In another configuration, the spinning cuphas an internal flange forming a lip, wherein the lip prevents beansfrom escaping the spinning cup, but allows chaff to escape the spinningcup. In yet another configuration, the roasting chamber comprises aspinning cup that is configured to move beans within the high intensitymicrowave regions.

In accordance with another aspect of the invention, the beans may bemoved within the roasting chamber with a rotating stirring rod, whichcauses the beans to circulate with the roasting chamber while they aresubjected to microwave energy. In one configuration, the stirring rod ispositioned proximate a bottom surface of the roasting chamber. Inanother configuration, the stirring rod is positioned along a sidewallof the roasting chamber.

In accordance with one aspect of the invention, a heating element may beused to heat air passing into the roasting chamber. The air being blowninto the airflow chamber may, for example, above ambient roomtemperature of about 20° C. up to about 245° C. to assist in theroasting process.

In another aspect, the present invention involves a roasting chamber forcontaining beans and a single-mode resonant microwave applicator forgenerating a standing microwave energy field comprising an array of oneor more anti-node high intensity microwave regions. The beans aresubjected to the microwave energy in the one or more high intensitymicrowave regions, sufficient for the beans to achieve a substantiallyuniform distribution of heat to cause the beans to roast.

In accordance with another aspect of the invention, a microwave deviceis provided for roasting cereal grain and seed beans includes amicrowave energy source; a single-mode resonant waveguide applicatorwherein the waveguide is configured to focus microwave energy from themicrowave energy source at one or more regions within the waveguide; aroasting chamber for heating beans, and an outlet in communication withthe roasting chamber for discharging roasted beans; and at least one airsource for circulating air within the lower portion of the roastingchamber and for passing air from the lower portion of the roastingchamber to the upper portion of the roasting chamber.

Because the system of roasting according to the present inventiongenerates smoke during the roasting process, the system may alsocomprise a venting system for venting smoke from the device. In oneembodiment, air from an air blower is used to transport the smoke fromthe roasting chamber through a smoke vent and into a vent duct of astructure within which the system is installed. In another embodiment,the air from the air blower is used to transport the smoke from theroasting chamber through a filter to remove smoke particles.

In accordance with another aspect of the invention, the improved systemand method of making roasted beans heats beans with microwaveelectromagnetic radiation by creating high intensity microwave regionswithin a roasting chamber. The beans are heated in the high intensitymicrowave regions until they roast to a desired degree. During theprocess, airflow that passes through the roasting chamber from a lowerportion of the chamber to an upper portion of the chamber may be used toremove chaff from the roasting chamber.

In one aspect, the present invention also contemplates novel methods forroasting beans, comprising moving beans within a roasting chamber andsubjecting the beans to focused microwave energy sufficient to cause thebeans to roast, resulting in roasted beans. In yet another aspect, thepresent invention comprises a method for roasting beans, comprisinggenerating a standing microwave energy field in a single-mode resonantmicrowave applicator, wherein the standing microwave energy fieldcomprises an array of one or more high intensity microwave regions andsubjecting beans to the microwave energy in the one or more highintensity microwave regions, sufficient to cause the beans to roast andproduce roasted beans.

In one embodiment, a method is provided that comprises the steps ofpassing electromagnetic microwave radiation through a roasting chamberand maintaining at least one anti-node of at least one microwave at afixed location within the roasting chamber. The beans are heated withthe microwave radiation at approximately the location of the one or moreanti-node.

In another aspect, the present invention provides a method of roastingbeans, comprising moving beans within a roasting chamber with a stirringdevice or airflow; and subjecting the beans to microwave energysufficient to cause the beans to roast, resulting in roasted beans. Inone embodiment, the microwave energy is focused microwave energy.

In yet another aspect, the present invention provides a method forroasting beans, comprising generating in a single-mode resonantmicrowave applicator a standing microwave energy field comprising anarray of one or more anti-node high intensity microwave regions, andsubjecting beans to the microwave energy in the one or more highintensity microwave regions, sufficient for the beans to achieve asubstantially uniform distribution of microwave energy heat to cause thebeans to roast.

In yet another aspect, the present invention provides a method forroasting beans comprising generating in a single-mode resonant microwaveapplicator a standing microwave energy field comprising an array of oneor more high intensity microwave regions; providing a roasting chamberencompassing the one or more high intensity microwave regions;delivering beans to the roasting chamber, wherein the beans are movedthrough the microwave high intensity microwave region within theroasting chamber to achieve a highly uniform distribution of microwaveenergy heat until roasted; and selectively discharging roasted beansfrom the roasting chamber.

In one aspect, the present invention includes the roasting chamber beingsmaller than the wavelength of the microwave energy being passed throughthe roasting chamber, such that the beans can circulate around andthrough the high intensity microwave region located within the roastingchamber. In one particular embodiment, the diameter of the roastingchamber is between about 1.75 inches (4.45 cm) and about 3 inches (7.62cm). In another embodiment, the diameter of the roasting chamber isbetween about 2 inches (5.08 cm) and about 2.5 inches (6.35 cm). Thesmall diameter of the roasting chamber subjects the beans to a high doseof microwave energy, causing it to roast rapidly. Movement of the beanswithin the roasting chamber makes the bean heat evenly to provide anevenly roasted bean. Thus, the present invention allows for rapidroasting without many of the drawbacks identified in the art.

In another aspect, the single-mode resonant microwave applicatorgenerates a standing microwave pattern comprising an electric fielddistribution of n half-wavelengths, where n is an integer. This mayinclude where n is greater than 1.

In one aspect, the present invention may include a plurality of roastingchambers. The microwave energy may be channeled such that each roastingchamber has a high intensity microwave region disposed therein and sothat the beans move within the high intensity microwave region.

In one aspect, the single-mode resonant microwave applicator may beconfigured to generate microwave energy at a frequency from betweenapproximately 800 MHz and 30 GHz. In some aspects, the microwavefrequency is from between approximately 1 GHz to 5 GHz. In more typicalapplications, the microwave frequency is from between approximately 2GHz to 3 GHz. Many commercial microwaves use microwave frequency atabout 2.54 GHz. The microwave energy source may comprise a magnetron asis known in the art of microwave ovens or one or more microwave emittingchips. Such microwave chips may be arranged in an array to providesufficient microwave energy for roasting the beans. In addition, becausesuch the microwave chips are capable of emitting microwaves at variousfrequencies and energies, a control system may be employed to vary themicrowave energy being emitted from the microwave chips to controlroasting at various stages of the roasting process. For example, themicrowave energy from the chips can be varied during the roastingprocess so that the beans are roasted at different microwave energies atdifferent stated of roasting.

In accordance with one aspect of the present invention a single-moderesonant microwave applicator may be configured to generate microwaveintensity within the roasting chamber to subject the beans to microwaveenergy sufficient to roast one or more of the beans within approximately25-50 seconds. Thus, an entire batch of beans may be roasted in lessthan 30 seconds depending on the desired roast.

In one aspect, the present invention may include a device with two ormore microwave energy sources such that the two or more microwave energysources constructively interfere at approximately the same locationwithin the roasting chamber.

In another aspect, the present invention may include a device forcontinuously feeding beans into the roasting chamber. In one embodiment,the present invention includes a conveyor or bean feeding system formoving the beans through the focused microwave energy in a continuous orsemi-continuous process.

According to the National Coffee Association's website atwww.ncausa.org, “Roasting is both an art and a science. It takes yearsof training to become an expert roaster with the ability to ‘read’ thebeans and make decisions with split-second timing. The differencebetween perfectly roasted coffee and a ruined batch can be a matter ofseconds.” The systems and methods of the present invention for roastingcoffee beans eliminates the guesswork of prior art roasting methods byproviding a rapid and controlled roasting of coffee beans using focusedmicrowave energy.

These and other aspects of the present invention are realized as shownand described in the following figures and related description.

BRIEF DESCRIPTION OF THE DRAWINGS

When considered in connection with the following illustrative figures, amore complete understanding of the present invention may be derived byreferring to the detailed description. In the figures, like referencenumbers refer to like elements or acts throughout the figures.

FIG. 1 shows a perspective view of an apparatus for roasting coffee inaccordance with the principles of the present invention.

FIG. 2 shows a cross-sectional side view of another embodiment of anapparatus for roasting coffee in accordance with the principles of thepresent invention.

FIG. 3 shows a top view of a roasting chamber for roasting coffee inaccordance with the principles of the present invention.

FIG. 4 shows a top view of another embodiment of a roasting chamber forroasting coffee in accordance with the principles of the presentinvention.

FIG. 5 shows a top view of yet another embodiment of a roasting chamberfor roasting coffee in accordance with the principles of the presentinvention.

FIG. 6 shows a top view of the roasting chamber for roasting coffee showin FIG. 5.

FIG. 7 shows a cross-sectional side view of yet another embodiment of anapparatus for roasting coffee in accordance with the principles of thepresent invention.

FIG. 8 shows a cross-sectional side view of yet another embodiment of anapparatus for roasting coffee in accordance with the principles of thepresent invention.

FIG. 9 shows a schematic block diagram of a method of roasting coffee inaccordance with the principles of the present invention.

FIG. 10 shows a side view of a wave guide and roasting chamber inaccordance with the principles of the present invention.

FIG. 11 shows a side view of an alternative embodiment of a wave guideand roasting chamber in accordance with the principles of the presentinvention.

FIG. 12 shows a side view of another alternative embodiment of a waveguide and roasting chamber in accordance with the principles of thepresent invention.

FIG. 13 shows a side view of yet another embodiment of an apparatus forroasting coffee in accordance with the principles of the presentinvention.

It will be appreciated that the drawings are illustrative and notlimiting of the scope of the invention, which is defined by the appendedclaims. The embodiments shown accomplish various aspects and objects ofthe invention. It is appreciated that it is not possible to clearly showeach element and aspect of the invention in a single figure, and assuch, multiple figures are presented to separately illustrate thevarious details of the invention in greater clarity. Similarly, notevery embodiment need accomplish all advantages of the presentinvention. Elements and acts in the figures are illustrated forsimplicity and have not necessarily been rendered according to anyparticular sequence or embodiment.

DETAILED DESCRIPTION

The invention and accompanying drawings will now be discussed inreference to the numerals provided therein so as to enable one skilledin the art to practice the present invention. The drawings anddescriptions are exemplary of various aspects of the invention and arenot intended to narrow the scope of the appended claims. Unlessspecifically noted, it is intended that the words and phrases in thespecification and the claims be given their plain, ordinary andaccustomed meaning to those of ordinary skill in the applicable arts. Itis noted that the inventors can be their own lexicographers. Theinventors expressly elect, as their own lexicographers, to use only theplain and ordinary meaning of terms in the specification and claimsunless they clearly state otherwise and then further, expressly setforth the “special” definition of that term and explain how it differsfrom the plain and ordinary meaning. Absent such clear statements ofintent to apply a “special” definition, it is the inventors' intent anddesire that the simple, plain and ordinary meaning to the terms beapplied to the interpretation of the specification and claims.

The inventors are also aware of the normal precepts of English grammar.Thus, if a noun, term, or phrase is intended to be furthercharacterized, specified, or narrowed in some way, then such noun, term,or phrase will expressly include additional adjectives, descriptiveterms, or other modifiers in accordance with the normal precepts ofEnglish grammar. Absent the use of such adjectives, descriptive terms,or modifiers, it is the intent that such nouns, terms, or phrases begiven their plain, and ordinary English meaning to those skilled in theapplicable arts as set forth above.

Further, the inventors are fully informed of the standards andapplication of the special provisions of 35 U.S.C. §112(f) or pre-AIA 35U.S.C. §112 ¶6. Thus, the use of the words “function,” “means” or “step”in the Detailed Description of the Invention or claims is not intendedto somehow indicate a desire to invoke the special provisions of 35U.S.C. §112(f) or pre-AIA 35 U.S.C. §112 ¶6 to define the invention. Tothe contrary, if the provisions of 35 U.S.C. §112(f) or pre-AIA 35U.S.C. §112 ¶6 are sought to be invoked to define the inventions, theclaims will specifically and expressly state the exact phrases “meansfor” or “step for” and the specific function (e.g., “means forroasting”), without also reciting in such phrases any structure,material or act in support of the function. Thus, even when the claimsrecite a “means for . . . ” or “step for . . . ” if the claims alsorecite any structure, material or acts in support of that means or step,or that perform the recited function, then it is the clear intention ofthe inventor not to invoke the provisions of 35 U.S.C. §112(f) orpre-AIA 35 U.S.C. §112 ¶6. Moreover, even if the provisions of 35 U.S.C.§112(f) or pre-AIA 35 U.S.C. §112 ¶6 are invoked to define the claimedinventions, it is intended that the inventions not be limited only tothe specific structure, material or acts that are described in theillustrated embodiments, but in addition, include any and allstructures, materials or acts that perform the claimed function asdescribed in alternative embodiments or forms of the invention, or thatare well known present or later-developed, equivalent structures,material or acts for performing the claimed function.

In the following description, and for the purposes of explanation,numerous specific details are set forth in order to provide a thoroughunderstanding of the various aspects of the invention. It will beunderstood, however, by those skilled in the relevant arts, that thepresent invention may be practiced without these specific details. Inother instances, known structures and devices are shown or discussedmore generally in order to avoid obscuring the invention. In many cases,a description of the operation is sufficient to enable one to implementthe various forms of the invention, particularly when the operation isto be implemented in software. It should be noted that there are manydifferent and alternative configurations, devices and technologies towhich the disclosed inventions may be applied. Thus, the full scope ofthe inventions is not limited to the examples that are described below.

Various aspects of the present invention may be described in terms offunctional block components and various processing steps. Suchfunctional blocks may be realized by any number of hardware or softwarecomponents configured to perform the specified functions and achieve thevarious results.

Various representative implementations of the present invention may beapplied to any system for roasting beans or other food products or foodstuff. Thus, while there is disclosed improved systems, devices andmethods for roasting coffee beans, it will be understood that referencesin the following disclosure to systems and devices are also applicableto other food stuff and methods, which utilize related structures forthe processes recited. Similarly, references to methods are alsoapplicable of systems and devices, which perform the processes in theoperation of the recited devices. It will be appreciated that numerouschanges may be made to the present invention without departing from thescope of the claims, including but not limited to combinations ofelements or structures of the various illustrated embodiments.

As used herein, the following terms have the meaning set forth below:

The term “bean” means any one or more of several varieties of beans,such as coffee beans, that are commonly roasted to produce a productthat can be ground or otherwise processed for producing a beverage orfood product. Suitable beans capable of being roasted include, forexample, coffee beans, cocoa beans, and the like. Although thespecification herein refers frequently to “coffee” as the exemplarybean, it is understood that the various apparatus, device and methodembodiments described herein may be used for roasting other beans,grains or seeds other than coffee beans and that the scope of the claimsreferring to a “bean” or “beans” encompasses all such varieties ofbeans, grains or seeds capable of being roasted, and shall not belimited by any particular references in the specification to “coffeebeans.”

The term “cracked bean” means a bean that has been heated sufficientlyto cause the bean to expand and emit an audible crack.

The term “roasted bean” means a bean that has been heated sufficientlyto achieve a desired roast.

The term “focused microwave energy” means microwave energy that has beendirected or focused into a defined area, resulting in a substantiallystable and homogeneous field pattern surrounding the load being subjectto the microwaves. Focused microwave energy may be generated, forexample, by reflecting microwaves in a multi-mode microwave applicatorhaving multiple resonant modes of microwave energy propagation, or bygenerating a standing wave pattern in a single resonant mode (i.e.,single-mode) microwave applicator, where the standing microwave patterngenerates microwaves that constructively interfere to generate stableareas of high intensity microwave energy.

The term “high intensity microwave region” means a region of focusedmicrowave energy in a microwave applicator, wherein the microwaves areof sufficiently high intensity to cause rapid heating and roasting ofbeans. A high intensity microwave region typically includes the locationof maximum energy intensity. Although a high intensity microwave regionmay encompass the location of energy maxima, it does not necessarilyinclude the point of energy maxima. Because, in a single-mode resonantmicrowave applicator, the energy intensity varies sinusoidally from theenergy minimum (the node, where electro-magnetic waves destructivelyinterfere) and the energy maximum (the anti-node, where theelectro-magnetic waves constructively interfere), a high intensitymicrowave region may also encompass the region of energy intensity thatis less than the energy maximum while excluding the actual location ofenergy maximum. A roasting chamber may encompass two high intensitymicrowave regions, without encompassing the points of energy maxima,where the perimeter of the roasting chamber (i.e., the sidewalls) passesthrough the region between the two energy maxima without actuallypassing through the energy maxima. Accordingly, a “high intensitymicrowave region” shall be construed to comprise those locations havinga microwave energy greater than the microwave energy minima and having astable well-defined microwave energy maxima.

The term “single-mode,” as used in reference to microwave applicatorsherein, means that the superposition of incident and reflect waves in aresonant cavity results in a standing wave pattern with a singleresonant mode of microwave energy, thereby generating high intensitymicrowave regions containing energy maxima that are stable atwell-defined and predictable positions within the applicator. Incontrast, traditional multi-mode microwave applicators propagatemicrowaves with multiple modes of energy, each with varying intensityand at irregularly spaced intervals. A single-mode resonant microwaveapplicators establish significantly higher electric field strengthscompared to a traveling wave or a multi-mode applicator, and aregenerally more compact, as the dimensions of the resonant cavities are afunction of the wavelength typically used for microwave heating (e.g.,2.45 GHz) of food articles. The particular size and dimensions of asingle-mode microwave applicator can be determined by those skilled inthe art of microwave heating, by utilizing Maxwell equations, whichcontain all the necessary parameters needed to define the standing wavepattern desired to be established in a particular case, including thegeometry and dimensions of a resonant waveguide applicator operating insingle-mode.

It is further understood that use of definite articles such as “the” or“a” shall be construed to include one or more elements and shall not beconstrued to be limited to a single element. Elements shall be limitedto single elements only if expressly modified by a term such as“single,” “one,” “sole,” “only,” or the like.

The present invention generally relates to novel devices and methods forroasting beans which may achieve a variety of desired outcomes, such asdecreased roasting times and improved roasting characteristics as setforth herein. The novel devices and method may utilize focused microwaveenergy to create a high intensity microwave field density that moreuniformly heats beans at a high rate to cause the beans to achieve adesired final bean temperature, depending on the desired roast,substantially simultaneously and thereby roast more evenly andcompletely. Although the use of multi-mode microwave devices have beenused in the art for roasting coffee beans, the present invention relatesto the discovery that focused microwaves, such as single-mode microwaveapplicators, may result in improved roasting efficiency, as well asimproved speed of roasting. In addition, the focused microwaves mayresult in improved roasted beans having lower density, larger size,higher roasting efficiency and improved taste characteristics.

The devices and methods described herein confer significant advantagesover the prior art, including, for example, providing devices that aresignificantly smaller in size, which enables ease of storage andimproved portability, and consume significantly less energy. Forexample, such devices may be used to provide roasted coffee beans foremergency humanitarian aid, disaster relief or military purposes, wherethere is a need to produce high volumes of roasted beans, inexpensively,in remote locations where there may be no significant energyinfrastructure. The portability of the devices disclosed herein may alsobe a significant advantage where there is a demand for large quantitiesof freshly roasted coffee beans in restaurants or production facilities,as the devices enable high volume output of freshly roasted coffeebeans, and avoid the need of advance production of roasted coffee beansthat may not be fresh or that requires roasting off-site andtransportation.

While various embodiments implementing different aspects of the presentinvention are discussed below, it has been found in accordance with theprinciples of the present invention than multiple advances may beachieved in the roasting of beans, and in particular the roasting ofcoffee beans. For example, in accordance with aspects of the inventionit has been found that improvements in roasting coffee beans can beachieved by placing coffee beans in a roasting chamber disposed within awithin a single high intensity microwave region, i.e. the chamberclosely surrounds or encompasses the area of peak energy of a standingmicrowave signal. As the beans move within the high intensity microwaveregion, the beans are able to heat rapidly, thereby causing the beans toheat and roast in a much shorter period of time than conventionalconduction, convection, air or microwave roasting systems known in theart. Additionally, all of the beans are subject to a substantially equalamount or dose of microwave energy over time to thereby moresubstantially simultaneously and uniformly heat each bean thanconventional methods. This results in the beans being more rapidly anduniformly roasted in a relatively short period of time.

As compared to prior art roasting methods, the present inventionsignificantly improves roasting time. Using a high intensity microwavedevice, in accordance with the present invention, roasting started andwas completed within a significantly shorter period of time. With thetime to first crack happening in as little as about 13-20 seconds, (onaverage within about 18 seconds), while roasting was completed within24-50 seconds depending on the desired roast. Thus, the methods andsystems of the present invention provide a significant improvement inthe time it takes of initiate and finish roasting a batch of greencoffee beans, showing a reduction in the average time of over 1200% forthe darkest roasts.

Not only do the systems and methods of the present invention roast thecoffee beans faster, it has been found that systems and methods of thepresent invention produces uniformly roasted beans. In addition, therapid heating and roasting of the beans in accordance with the presentinvention resulted in roasted beans that have equivalent flavor as thosethat are roasted using traditional bean roasting techniques.Accordingly, the methods and systems of the present invention providesignificant improvements to time required to roast coffee beans whilemaintaining the consistency, quality, flavor and aroma of the roastedcoffee beans.

It has also been discovered that the use of high intensity microwaves inaccordance with the present invention result in a significant reductionin power consumption. For example, a typical roasting process consumessignificant energy to heat the roasting pan and to maintain thetemperature of the roasting pan for the time necessary to roast thebeans. A standard kitchen microwave consumes a significant amount ofenergy when operated for an extended period of time to roast coffeebeans according to the prior art systems. In contrast, the use of afocused microwave device in accordance with the present inventionconsumes significantly less energy due to the reduced roasting times.The methods and devices of the present invention further result insignificant reduction in energy consumption and cost savings.

Finally, the methods and devices of the present invention also result ina significant reduction or elimination of overly roasted beans. Roastedbeans made by the methods and devices of the present invention, whencompared to roasted beans made by methods and devices previously used(such as standard roasting pans), show significant reduction in burnedor charred beans, which could potentially be toxic or carcinogenic.

Systems and Devices

The basic configuration of the systems and devices of the presentinvention comprises a microwave emitter, such as a magnetron or amicrowave emitting semiconductor chip, connected to a microwave antennafor emitting microwave energy into a roasting chamber. The systems anddevices may include a waveguide cavity or microwave focusing device,such as a single-mode resonant cavity, within which a roasting chamberis located. The purpose of the microwave cavity and associated hardwareis to maximize the energy field at the load (the beans) and optimize themicrowave coupling efficiency. The microwave applicators of the presentinvention generate high intensity microwaves within the roasting chamberto subject the beans to microwave energy sufficient to roast the beansto various degrees depending upon the desired roast, such as by way ofexample and not by limitation light roast, medium roast or dark roast.

One embodiment of a system for roasting beans in accordance with thepresent invention is shown in FIG. 1. A bean roasting system, generallyindicated at 10, utilizes a microwave energy emitter for producingmicrowave energy within a roasting chamber within which a batch ofuncooked beans 12 dispensed from a hopper 14 are positioned. Theroasting system 10 is a self-contained unit that allows a user to selectthe degree of roast. For example and not by way of limitations, aselector knob 16 allows the user to select a light, medium or dark roastof the beans 12. The, user then presses the start button 17 to roast thebeans according to the selected roast. Of course, the system forroasting beans 10 can be configured to in provide a number of roastingoptions as will be discussed in more detail herein. Once the roast iscomplete, as indicated by the display screen 18, the roasted beans aredispensed into a container to be used in making a brewed beverage, suchas espresso or coffee, depending on the roast and subsequent grinding ofthe beans.

Because the roasting of beans 12, such as coffee beans, generates smoke,the system 10 is provided with a smoke filtration system 20. The smokefiltration system draws smoke from the roasting process through aconduit 22 and into filter 24. Alternatively, the system 20 could simplydraw the smoke from the machine to a ventilation system of a home orbuilding in which the roasting system 10 is installed. The filter 24 maycomprise a HEPA filter capable of filtering smoke, an oil-based filter,water based filter, or other smoke filtration systems known in the art.

Referring now to FIG. 2, there is shown a bean roasting system,generally indicated at 100. The bean roasting system 100 includesmicrowave energy emitter 114 for producing microwave energy within aroasting chamber 118. Appropriate microwave energy emitters 114 areknown and may be selected according to various design considerationsknown to those skilled in the art and determined without undueexperimentation. For example, some microwave energy emitters comprise amagnetron 122 for generating microwaves and a magnetron antenna 124disposed within a waveguide 126. Other microwave energy emitterscomprise microwave semiconductor ships that may be arranged in an arrayto produce sufficient microwave energy within the waveguide to rapidlyroast the beans. The waveguide 126 is configured to form a standing wavewithin the waveguide 126. The waveguide 126 thus serves to form astanding wave within the waveguide, and because the roasting chamber 118is positioned within the waveguide, the waveguide also serves as amicrowave applicator.

The magnetron 122 may generate microwave energy at any frequencysuitable for roasting beans 12. Generally, beans may be heated withmicrowaves at a frequency ranging from 1 MHz up to 30 GHz. The range offrequencies more commonly used is from about 400 MHz to about 20 GHz.The ISM bands commonly used for industrial, scientific and medical uses(including heating/cooking food products), as prescribed by certaingovernment regulatory agencies, include 896 MHz, 915 MHz and 2.45 GHz.For example, in some embodiments, the magnetron is tuned to generatemicrowave energy at a frequency that maximizes the rapid oscillation ofwater molecules in the load being heating, such as 2.45 GHz. As will beapparent to those skilled in the art, other operating frequencies mayalso be used effectively. The present invention contemplates use ofmicrowave energy at any frequency suitable for roasting beans.

The selection of appropriate microwave generators is considered to bewithin the ordinary skill in the art. It is understood that typicalmicrowave generators utilize magnetron oscillators, which may includecontinuous wave generators to produce a relatively narrow outputfrequency spectrum for use with small loads, as in the case of smallbatch volumes of beans. Microwave emitting semiconductor chips are alsoconsidered to be useful as an appropriate microwave generator for thebean roasting devised of the present invention.

Microwave Focusing Device

The present invention employs focused microwaves as a means of creatinghigh intensity microwave energy for rapid high-temperature roasting ofcoffee beans. Microwave energy may be focused, for example, byreflecting microwaves in a multi-mode applicator so as to create astable and homogeneous “high intensity microwave region” (defined below)at a defined location, such as within a small roasting chamber.Alternatively, microwave energy may be focused through use of adaptivemicrowave phased arrays to concentrate the microwave energy at apredetermined area. For example, suitable adaptively focused microwavesystems may be constructed having a phased array of multiple radiatingantenna elements for a tightly focused microwave beam having a maximumdimension on the order of 2-10 cm or larger, as described by Fenn A J,Adaptive Antennas and Phased Arrays for Radar and Communications,Norwood, Mass., Artech House Publishers, 133-160 (2008). Alternatively,microwave energy may be focused by use of a single-mode microwaveapplicator, which generates a stable standing wave pattern having one ormore “high intensity microwave region” of energy maxima. Othertechniques and devices for focusing microwaves are also contemplated tobe within the scope of the present invention.

In accordance with the present invention, one particular microwaveenergy focusing device is shown in FIG. 2. The microwave energy focusingdevice of the present invention as shown in FIG. 2 comprises a waveguide126, which defines a microwave cavity 128 within which a roastingchamber 118 containing coffee beans 12 is located. The microwave energyfocusing device provides for high intensity focused microwave energywithin the roasting chamber 118 and creates one or more stableevenly-spaced microwave anti-node high intensity microwave regions inthe roasting chamber. The waveguide 126 is comprised of a plurality ofwalls 130-134 that form a substantially enclosed waveguide within whicha standing wave of microwave energy is generated by the microwaveemitter 144. The walls 130-134 are formed from waveguide material knownin the art that contains the microwaves within the waveguide 126. Theroasting chamber 118 is positioned within the waveguide where thestanding waves produces a high intensity microwave energy region (i.e.,a microwave energy maximum). Such high energy regions are referred toherein as “high intensity microwave regions.”

In addition to the use of a waveguide as discussed herein, the use offocused microwaves may be achieved by any one of several approaches. Forexample, in one embodiment, microwave energy may be focused byreflecting microwaves from a shaped surface that is highly reflective ofmicrowave energy, so that radiation emitted from the microwave source isreflected towards the roasting chamber containing the coffee beans.Microwaves may be focused by reflecting off a surface such as aparabolic dish, a horn antenna, a hemispherical dome, etc.Alternatively, microwaves may be focused by means of a microwave lens.

In other embodiments, the focused microwaves may be achieved by use of asingle-mode resonant microwave applicator. A single-mode resonantmicrowave applicator has the ability to create a standing wave pattern,which is generated by the interference of fields that have the sameamplitude but different oscillating directions. This interface generatesan array of nodes where microwave energy intensity approaches zero, andan array of antinodes where the magnitude of microwave energy is at amaximum. Single-mode resonant applicators are designed so that thedistance of the sample from the magnetron is such that the sample can beplaced at the antinodes of the standing electromagnetic wave pattern.Single-mode resonant applicators may be designed such that the standingelectromagnetic wave pattern generates an array of one or more anti-nodehigh intensity microwave regions where the magnitude of microwave energyis at a maximum. As further shown and described herein, these anti-nodesare generated at evenly spaced intervals (where there is a plurality)and are sufficiently stable and localized that a load can be accuratelyplaced within the anti-node high intensity microwave region withpredictable and repeatable results.

Referring again to FIG. 2, the single-mode resonant microwave applicatoris comprised of a shorted rectangular waveguide 126 that forms amicrowave cavity 128 comprising a metal tube of waveguide materialhaving a generally rectangular cross section and one or moreshort-circuit walls 130 and 132 at the ends of the metal tube. It iscontemplated that single-mode resonant microwave applicators may also beconstructed of tubular or circular waveguides. In another embodiment,the microwave focusing device may be circular self-tuning single-moderesonant cavity (made by CEM Corporation, Matthews, N.C.). In asingle-mode resonant microwave applicator, the superposition of theincident and reflected waves establish a standing wave pattern that isstable, well-defined in space, and has evenly and predictably spacedpositions of energy maxima. These features enable a dielectric material,such as coffee beans, to be placed in one or more localized positions ofmaximum energy or concentrated electric field (referred to, herein, as a“high intensity microwave region”) for optimum transfer of theelectromagnetic energy to the dielectric material. In some embodiments,the single-mode resonant microwave applicator generates a standingmicrowave pattern comprising an electric field distribution of nhalf-wavelengths, where n is an integer. In some embodiments, n isgreater than 1. In some embodiments, n=1, 2, 3, 4, 5, 6, 7, 8, 9 or 10,or greater.

In some embodiments, the single-mode resonant microwave applicator maybe configured to generate a plurality of anti-node high intensitymicrowave regions. In some embodiments, as shown in FIG. 2, at least oneof the one or more high intensity microwave regions is located withinthe roasting chamber. In other embodiments, the roasting chamberencompasses a single high intensity microwave region. In otherembodiments shown and described herein, the roasting chamber encompassesa plurality of high intensity microwave regions. For example, the devicemay comprise a plurality of roasting chambers, wherein each highintensity microwave region is located within a single roasting chamber.In other embodiments, a single roasting chamber may span two adjacenthigh intensity microwave regions.

In some embodiments, the device may include two or more microwave energysources such that the two or more microwave energy sourcesconstructively interfere at approximately the same location within theroasting chamber.

Those skilled in the art understand that the choice of waveguide sizedepends on such considerations as operating frequency, power rating,component availability and cost. Various waveguide sizes commonly usedfor industrial microwave heating include 2450 MHz (S band) and 915 MHz(L band) include. For example, a WR284 (7.21 cm×3.40 cm) waveguide isoften the preferred choice for 2.45 GHz operation at average powerlevels of up to 6 kW. Waveguides may be made of such materials asaluminum, copper, or stainless steel.

The length of such waveguides may vary, depending on the number of highintensity microwave regions desired in the waveguide. Microwavewaveguide cavities may be designed to support any one of various TE₁₀rectangular waveguide resonant modes, including TE₁₀₁, TE₁₀₂, TE₁₀₃,TE₁₀₄, TE₁₀₅, etc., which generate 1, 2, 3, 4 and 5 high intensitymicrowave regions, respectively. Additional high intensity microwaveregions may be utilized advantageously in high volume manufacture ofcoffee beans. In accordance with certain embodiments of the invention, aroasting chamber for roasting coffee beans may encompass one or morehigh intensity microwave region within a single high intensity microwaveregion. In some embodiments, the roasting chamber encompasses a singlehigh intensity microwave region. In other embodiments, the roastingchamber encompasses two high intensity microwave regions. In someembodiments, the entire waveguide comprises the roasting chamber, andcoffee beans may pass through a plurality of high intensity microwaveregions as they cascade down the length of the waveguide. In yet otherembodiments, the devices of the present invention may include multipleoutlets corresponding to each of the one or more roasting chambers.Thus, by using multiple roasting chamber and multiple outlets, one maysignificantly increase the quantity of roasted beans produced.

It is also understood that the design of waveguides may requireappropriate isolators to allow microwave power to pass through in theforward but not reverse direction, so as to protect the microwavegenerator (i.e., the magnetron) from the damaging effects of reversepower. Alternatively, microwave devices may also include circulators,which do not absorb power and therefore require a separate “dummy”waveguide load connected to the circulator to absorb the reverse power.

The systems and devices of the present invention may also includeimpedance tuners, which couple microwave power to a load by matching therespective complex impedances between the load and the microwave powersource.

In some embodiments, the present invention contemplates achievingenhanced heating uniformity in a single-mode applicator by reciprocatinga standing wave inside the applicator. For example, the system may splitthe generate microwave power into two equal and coherent wave fronts.The two forward power wave fronts are then diverted through rotatingphase shifters and then reflected back through the phase shifters beforebeing routed to opposite ends of the applicator. The two coherent wavefronts converge inside the applicator to generate a pattern of standingwaves. The phase shifters operate by rotating a thin dielectric slabinside the waveguide with its rotational axis in the plane of theelectric field. When the slab, having low dielectric loss and highdielectric constant characteristics, rotates between positionsperpendicular to and parallel with the waveguide centerline the phaseshift alternates sinusoidally from near zero to maximum. Adjusting theslab geometry varies the phase shift amplitude. Rotating both phaseshifters synchronously and exactly 90 degrees out of phase with eachother will then cause a sinusoidal reciprocation of the standing wavepattern inside the applicator at constant amplitude.

In one particular embodiment, for example, the microwave cavity may be asingle-mode resonant cavity furnace, comprising a rectangular waveguidedesigned to support TE₁₀₃ rectangular waveguide mode, and is constructedfrom WR284 copper waveguide (7.21 cm×3.40 cm). The guide wavelength at2.45 GHz in WR-284 is λg=23.12 cm and the total length of the furnacecavity is approximately l=1.5λg=34.8 cm. A bean loading inlet is locatedat approximately 17.50 cm from the source end (near the half-way pointfrom each end), where the roasting chamber is located at a field maximum(a high intensity microwave region) at resonance.

As will be appreciated, those skilled in the art may construct and useother single-mode resonant cavity furnaces having different dimensionsthat are suitable for roasting coffee beans. Larger single-mode resonantcavity furnaces may be used, for example, to roast larger quantities ofcoffee on a commercial or industrial scale.

In addition, the present invention further contemplates that highintensity focused microwaves may be generated at a predetermined andstable location with the use of microwave focusing devices, such asmicrowave reflectors and lenses. For example, microwave reflectors maybe used, having a parabolic or hemispherical shape, for focusingmicrowaves at a specific location.

As shown in FIG. 2, the bean roasting device 100 is contained within ahousing 140 that houses and supports the various components. In order tosubject the beans 12 within the roasting chamber 118 to a substantiallyequal dose of microwave energy, the roasting chamber 118 is positionedproximate the energy maxima of the standing wave of microwaves withinthe waveguide 126 that is generated by the magnetron 122. In addition,in this embodiment, the roasting chamber is comprised essentially of acylindrical cup 118′ that is spun or rotated relative to the waveguide126 by a rotating shaft 142. The shaft 142 is supported by a bearingassembly 144 and is rotated by a motor 146 that is coupled to the shaftwith a belt and pulley system 148. The cup 118′ is rotated by the shaft142 at a high rate (e.g., about 300 to 500 rpm or more) to cause thebeans 112 to line the inside wall of the cup 118′ due to centrifugalforce. By having the beans 12 forming a single layer of beans along theinside wall of the cup 118′ as the cup 118′ spins, each bean 12 isexposed to substantially the same dose of microwave energy over time sothat each bean 12 is roasted at the same rate to cause consistentroasting of the beans 12 throughout the batch.

A fan or blower 150 is coupled to an exterior wall of the housing 140 tocool the magnetron 122 and other electronic components, such as powersupply transformer 154 and control circuitry 156. The bottom of the cup118′ includes ports that are small enough to prevent beans 12 frompassing there through but that allow air from the blower to pass aroundthe magnetron and through the cup 118′. Because the beans 12 emit wateras they are roasted, the air from the blower 150 helps to dry the beansas they are roasted to prevent the resulting chaff from sticking to theinside of the cup 118′.

Roasting Chamber

As illustrated in the accompanying drawings, the system and devices ofthe invention includes a roasting chamber 218 for containing the coffeebeans (not shown) while being heated. The roasting chamber 218 isconfigured to contain the coffee beans within a defined area thatencompasses one or more high intensity microwave regions. In someembodiments, the microwave energy focusing device, such as waveguide126, is configured such that at least a portion of one microwave energymaxima is located within the roasting chamber 218. In some embodiments,the roasting chamber 218 is constructed so as to permit or cause thebeans to move within or through one or more high intensity microwaveregions. In some embodiments, the roasting chamber 18 encompasses asingle high intensity microwave region or a portion of a single highintensity microwave region. In other embodiments, the roasting chambermay encompass more than one high intensity microwave region, or aportion of more than one high intensity microwave region. In someembodiments, the roasting chamber is constructed of a material that isgenerally transparent to microwaves, such as Teflon, glass, plastic orceramic, so as to allow the microwaves to pass through the roastingchamber walls and heat coffee beans disposed within the roastingchamber. The dimensions of the roasting chamber wall may also varywithout significantly altering the microwave characteristics. By way ofexample, the roasting chamber wall may, for example, be anywhere from1-15 cm, or in come embodiments from 2-10 cm, or in other embodimentsfrom 3-5 cm. A suitable thickness would, for example, be approximately 4cm.

In some embodiments, the devices of the present invention may comprise aplurality of high intensity microwave regions within a single microwaveapplicator. In such cases, the devices may also contain a plurality ofmultiple roasting chambers within the microwave applicator. It isfurther understood that a single roasting chamber may encompass morethan one high intensity microwave region. The roasting chamber need notbe concentric with a single high intensity microwave region. Theroasting chamber may, for example, pass through the high intensitymicrowave region on one side of the roasting chamber while the otherside of the roasting chamber is not located in a high intensitymicrowave region. Similarly, the roasting chamber may pass through allor part of a high intensity microwave region on one side of the roastingchamber, while passing through all or part of a high intensity microwaveregion on the other side of the roasting chamber. In such cases, thecoffee beans may achieve a sufficiently high level of high intensitymicrowave heating as long as they are cycling through the roastingchamber and through the separate high intensity microwave regions fastenough that the heating effect of the high intensity microwave regionaverages out.

In some embodiments, the roasting chamber 218 for heating coffee beansmay include a lower portion 230 and an upper portion 232. The lowerportion 230 may be disposed within the waveguide cavity 128 at thelocation of focused microwave energy within the waveguide. The roastingchamber 218 is configured to be a spinning cup as previously described.The bottom surface 233 is provided with a plurality of apertures 234through which air can pass as previously discussed with reference toFIG. 2.

FIG. 4 is an alternative embodiment of a roasting chamber 250 accordingto the present invention. The roasting chamber 250 is comprised of acylindrical cup 252 that is configured to be fixed in place relative tothe waveguide. A rotating member 254, such as a bar or paddle ispositioned proximate the bottom 256 of the cup 252. The rotating member254 stirs the beans within the cup 256 as it spins at a relatively highrate (e.g., 300 rpm). The beans are thus rapidly circulated within thecup 256 while being roasted to expose substantially all of the beans ofa particular batch to a substantially similar dose of microwave energyover time so as to cause all of the beans within the cup 252 to roast atthe same rate and to cause each bean to substantially uniformly roast toprevent individual beans from having inconsistent roasting across thebean. As will be described in more detail, the bottom end 256 of the cup252 defines an opening 258 to cooperate with a bean dispensing systemonce the beans have been roasted. Likewise, as shown in FIG. 5, a cup260 having a configuration similar to the cup shown in FIG. 3 mayinclude a bean dispensing opening 262 that is opened and closed with arotating plate 264. The plate 264 is selectively movable between a firstposition in which the plate substantially covers the opening 262 toprevent beans from falling from the cup 260 to a second open positionshown in FIG. 6 in which beans can be dispensed through the bottom ofthe cup 260.

Referring again to FIG. 2, the roasting chamber 118 may be connected toat least one air source, such as the air blower 150, for circulating airwithin the lower portion of the roasting chamber 118 and/or for passingair from the lower portion of the roasting chamber 118 to the upperportion of the roasting chamber 118 and out of the top opening of theroasting chamber 118.

In some embodiments, the roasting chamber 118 may be configured to allowcoffee beans to move within and the through one or more high intensitymicrowave region within the roasting chamber. For example, the beans maybe moved through the high intensity microwave region by airflow withinthe roasting chamber 118 generated by the air source 150, such as ablower 150.

In another embodiment of the bean roasting apparatus of the presentinvention, generally indicated at 300, as shown in FIG. 7, the beans 12may be moved through the high intensity microwave region by a rotatingcontainer 302 within which the beans 12 are disposed. In someembodiments, the beans 12 may be moved through the high intensitymicrowave region by a combination of airflow and a moving container. Insome embodiments, the rotating container 302 may also include aninwardly facing lip, sufficient to prevent un-roasted coffee beans 12from being removed from the container 302 by airflow or by centrifugalforce of the rotating container.

As shown in FIG. 7, airflow is generated by an air source 320, whichthen passes around the magnetron 312 and into the container 302. The airflow from the blower 320 then draws smoke generated from the roastingprocess through the chimney or vent passage 322.

The roasting chamber 302 is stationary. A rotating member 324 isrotatably coupled to the cup 302 and positioned in a bottom portionthereof. The rotating member 324 is in the form of a stirring device,such as a rod or paddle that causes stirring or mixing of beans withinthe cup 302 during roasting. The stirring device may be formed from amaterial such as Teflon, glass, plastic or ceramic, so as to allow themicrowaves to pass through the stirring device. Such stirring, aspreviously discussed, provides a substantially even dose of microwaveenergy to each bean 12 during the roasting period. Alternatively, thestationary cup 302 may rely on airflow to move the coffee beans withinor through the high intensity microwave regions. Alternatively, aspreviously discussed, the roasting chamber may rotate or move so as tocause the coffee beans to move within or through the high intensitymicrowave regions. The air source may cause the beans to travel in agenerally circular path in the roasting chamber while the beans areheated to cause more equal roasting of the beans. In addition, the airmay be heated so as to further decrease the roasting times and to helpthe exterior of the bean to roast more rapidly as the inside of the beanis roasted with microwave energy. The same air source or an alternateair source may also be used lift roasted beans out of the roastingchamber. It will be appreciated that a bean has a much greater volumefor the given mass (which essentially remains the same before and afterroasting, less any dissipated moisture after roasting) and thus hasincreased drag compared to an un-roasted bean. The airflow through theroasting chamber may be configured to have sufficient velocity to carrya coffee bean out of the roasting chamber after the roasting process iscomplete. That is, the air flow through the bottom of the roastingchamber may be increased to carry out the roasted beans from theroasting chamber upon completion of roasting.

As further shown in FIG. 7, the rotating member 324 is rotated relativeto the cup 302 with the shaft of electric motor 330. In this embodiment,the magnetron 312 is positioned above the waveguide 340 with the antenna342 extending down into the waveguide 340. A capacitor 344, transformer346 and other circuitry 348 are positioned within the housing 350.

Roasting Chamber/Container

The roasting chamber functions to circulate un-roasted coffee beanswithin and through one or more high intensity microwave region of highintensity microwave energy, so as to achieve rapid and uniform heatingof the coffee beans. For example, the roasting chamber may comprise acontainer within which un-roasted coffee beans are disposed. Thecontainer may be cylindrical in shape or conical or funnel(frustoconical) in shape. In some embodiments, the container may beadapted to include one or more air inlets and an outlet. Airflow withinand through the container may be utilized to move the coffee beans andachieve a more even distribution of heating of the beans as the movementwithin and through the one or more high intensity microwave regionsresults in a sufficiently high average heating of the coffee beans.

In other embodiments, the container may be configured to rotate so as tomove the beans within or through one or more high intensity microwaveregion, with or without airflow, thereby achieving an average highintensity heating sufficient to cause rapid and uniform heating of thecoffee beans. In some embodiments, the container may be configured torotate so as to move the beans horizontally within or through one ormore high intensity microwave region, while also being configured toinclude an air inlet and air outlet for vertical airflow, so as toselectively remove roasted beans from the container with the upwardvertical flow of air after roasting. The rotation of the roastingchamber may also be used advantageously to hold coffee beans against theside wall of the roasting chamber by centrifugal force created byrotation of the roasting chamber, thereby increasing the required forceof airflow to remove the bean before roasting, and permitting increasedforce of airflow to achieve selective removal of roasted beans from thecontainer. Moreover, the rotation of the container further forcesun-roasted beans to line up against the side wall, creating a trajectoryof the beans at a constant radius through the one or more high intensitymicrowave region that is well-defined, so as to achieve a more uniformaverage high intensity heating of the beans.

The container may also be configured in the form of a cylinder or cone,with an inwardly facing lip at the top sufficient to prevent beans fromexiting the container when the container is rotating. While rotation ofthe container forces coffee beans to the top by centrifugal force, thelip prevents beans from exiting the container.

In another embodiment, the roasting chamber may be substantiallycylindrical in shape, with vertical side walls, with an inwardly facinglip at the top of the container. In embodiments utilizing verticalairflow to remove roasted beans, the inwardly facing lip is sized so asto prevent beans from exiting the container until roasting is complete.

Air Source

The roasting chamber may be connected to one or more air sources, suchas a fan or air blower, for creating airflow within the roasting chamberand causing the coffee beans to move within the roasting chamber. Insome embodiments, the device comprises one or more airflow inlets and anairflow outlet. The blower causes airflow to pass through the roastingchamber. In some embodiments, the blower is configured to cause airflowwithin or through the roasting chamber from a lower portion of theroasting chamber to an upper portion of the roasting chamber and throughthe airflow outlet of the roasting chamber.

The blower may be configured to cause airflow within the roastingchamber in a horizontal direction so as to cause the beans of coffee tocirculate within and through the microwave high intensity microwaveregion. The roasting chamber may further comprise an air input in theside wall of the roasting chamber, wherein the horizontal of airflowcomprises airflow input tangentially into the roasting chamber from theside wall of the roasting chamber at an angle generally perpendicular tothe radius of the cylindrical roasting chamber. The blower or other airsource may also be configured to cause airflow within the roastingchamber in an approximately circular path and move the coffee beansgenerally horizontally within the roasting chamber in an approximatelycircular path within and through the high intensity microwave region. Insome embodiments, the roasting chamber is cylindrical and substantiallycircular in cross-sectional shape and the blower is configured to causeairflow within the roasting chamber in an approximately circular pathand move the coffee beans horizontally within the roasting chamber in anapproximately circular path. In some embodiments, an air source may alsobe provided to cause airflow within and through the roasting chamber ina vertical direction, so as to selectively lift roasted coffee beansupwardly and out of the roasting chamber. For example, the device may beconfigured with two air blowers, air blower and a second air blower. Theblower may be configured to cause vertical airflow from a lower portionof the roasting chamber 18 upwardly to an upper portion 32 of theroasting chamber 18 and thereby selectively move the roasted coffee outof the roasting chamber when roasted.

In some embodiments, one or more air sources may be configured to createairflow in both a vertical and horizontal direction. For example, theblower may be configured to create airflow in an upwardly spiraldirection. Alternatively, the airflow may be configured to form a vortexwith the roasting chamber and/or outlet tube. Two separate air sourcesmay be utilized to provide vertical and horizontal airflow. The airflowmay be generated, for example, by a first blower and a second blower,wherein the first blower is configured to create airflow in a horizontaldirection and the second blower is configured to create airflow in avertical direction. Alternatively, single blower may be configured toprovide airflow in both a vertical and horizontal direction by providingtwo separate air ducts from the blower to each of the air inlets. Whereseparate first and second blowers are utilized, each blower may beconfigured to independently provide a different rate of airflow for thevertical and horizontal airflows. For example, one or more of theblowers may be configured to independently provide sudden or increasedairflow for the purpose of removing roasted beans of coffee from theroasting chamber. Similarly, the vertical and horizontal airflows mayindependently provide hot air or cold air.

In particular embodiments, the airflow has a flow-rate that will move avolume of beans through a high intensity microwave region sufficient torapidly and uniformly heat the load of unroasted beans, whilemaintaining the unroasted beans within the high intensity microwaveregion without being expelled.

In addition, in another embodiment, heated airflow may be used to removeresidual moisture from the roasted coffee beans.

Preheating

In accordance with another aspect, the present invention provides a heatsource for preheating the one or more beans prior to being disposedwithin the roasting chamber. In some embodiments, the devices of theinvention may include a heater for heating the airflow to be passedthrough the roasting chamber. The un-roasted coffee beans may bepreheated by the heated airflow so as to increase the efficiency of thefinal microwave roasting. Accordingly, in some embodiments, the systemsand devices may further comprise a heating element to cause heating ofthe airflow. In some embodiments, the air source or blower may includeheating elements, which heat the airflow. The air being blown into theairflow chamber may, for example, between ambient room temperature ofabout 20° C. to about 232° C., or alternatively from about 50° C. toabout 150° C., or alternatively from about 70° C. to about 180° C., oralternatively from about 80° C. to about 95° C. Thus, the coffee beansmay be preheated, without resulting in roasting, when heated to atemperature less than 196° C. (385° F.). In other embodiments, theroasting chamber within which the coffee beans are dispose may itself beheated. In yet other embodiments, the coffee beans may be preheatedwithin the storage container used to dispense the coffee beans into theroasting chamber.

In other embodiments, the systems and devices of the invention may alsocomprise a heat source for preheating the one or more beans prior tobeing disposed within the roasting chamber. For example, the beans maybe preheated with a heat source selected from one or more of a flame,infrared heat, convection heat or heat from a resistive element.

In some embodiments, the devices of the invention further comprise acontrol module for controlling the temperature, flow rate, and flow pathof the air.

Inlets/Outlets

As shown in FIG. 8, in some embodiments a coffee bean storage container420 is provided, which dispenses green coffee beans 422 through theportioning device 486 and into the roasting chamber 423. An inlet inplate 429 is configured to dispense a quantity of coffee beans into theroasting chamber 423. While shown above the roasting chamber, it iscontemplated that the inlet may be located either on the side wall, thebottom or the top of the roasting chamber 423. FIG. 8 shows an inletplate 429 into the top of the roasting chamber 423, allowing coffeebeans 422 to be dispensed into the roasting chamber 423 by force ofgravity. Coffee beans 422 may be dispensed into the roasting chamberfrom a storage chamber 420 that is connected to the roasting chamber 423by means of a dispensing tube. The storage chamber 420 may be locatedabove the roasting chamber 423, where it can dispense coffee beans tothe roasting chamber by gravity, or may alternative be located to theside of or below the roasting chamber, where coffee beans would need tobe dispense to the roasting chamber by means of a conveyor, lift,plunger or airflow. In some embodiments, the inlet plate 429 isconfigured to dispense the coffee beans 422 into the roasting chamber423 in such a manner that coffee beans 422 circulating within theroasting chamber 423 do not reenter the dispensing tube. For example,the inlet plate may connect to the roasting chamber at an angle, suchthat coffee beans circulating in one direction bypass the inlet at anacute angle relative to the angle coffee beans enter the roastingchamber through the inlet and do not reenter the dispensing tube.

In some embodiments, the storage chamber 420 may also include a meteringand dispensing device 486 for controlling the number of coffee beansbeing released into the roasting chamber 423 in batch mode.Alternatively, the metering and dispensing device 486 may control therate of flow of coffee beans being released into the roasting chamber423 for dispensing beans in a continuous mode. For example, the meteringand dispensing device 486 may regulate the rate of flow to enablecontinuous feeding beans into the roasting chamber 423. Such a meteringdevice includes, for example, a microphone for detecting the sound of abean roasting or a temperature sensor for detecting bean temperatureduring a roast, coupled to a controller that regulates one or moreprocess parameter, including air velocity, speed of circulating beans,input of new beans, output of roasted beans, microwave intensity, etc.The device of the invention further includes an outlet plate 429 at thebottom of the roasting chamber to selectively discharge roasted beansfrom the roasting chamber 423. An outlet tube 425 is coupled relative tothe outlet plate 429 of the roasting chamber 423 to direct the roastedbeans 422′ dispensed from the roasting chamber 423 to a grinding mill424.

The microwave devices of the present invention may also include any oneof numerous sensory inputs that regulate the flow of coffee beans intothe roasting chamber, the rate of airflow, the degree of preheating,etc. For example, the present invention contemplates the use of amicrophone roast detector for sensing the sound created by the roastingbean and/or the frequency of the noise of roasting, coupled with thebean flow metering unit that dispenses additional quantities of coffeewhen the roasting ceases or the frequency of roasting falls below aselected threshold. In addition, such inputs may include suddenincreased airflow to clean passageways of un-roasted beans or roastedbeans that may occasionally adhere to surfaces.

The use of high field intensity high intensity microwave regions forroasting coffee beans further enables novel bean feed approaches. Forexample, in some embodiments, beans may be sprayed onto a strip of paperhaving an edible adhesive surface and the strip of paper with adherebeans may then be fed through the high intensity microwave region wherethe beans roast and release from the paper, or alternatively roast andremain adhered to the paper.

As further illustrated in FIG. 8, a combination coffee bean roasting,grinding, portioning, and pressing device 410 is constructed inaccordance with the present invention with a mounted, detachabledelivery filter 414. While such systems for grinding, portioning andpressing coffee are known in the art, the device 410 of the presentinvention also includes a bean roasting device 421 to uniquely allow rawcoffee beans 422 to be freshly roasted for each batch of coffeeprepared.

Briefly described, the roasting, grinding, portioning, and pressingdevice 410 includes a whole bean coffee storage container 420 forstorage of coffee beans 422. Coffee grinding mills 424 are located underthe roasting device 421 and storage container 420. The coffee beans 422are ground in the mills and delivered from the grinding mills 424 into aground coffee collection chamber 440. The ground coffee 438 passes fromthe collection chamber 440 through a motor-driven, rotating pressingtool 450 directly into the detachable delivery filter 414, which istemporarily attached to the device 410. Specifically, the shape androtational motion of the pressing tool 450 causes the ground coffee 438to be directed through the tool 450 and into the delivery filter 414.

The motorized pressing tool 450 is biased downwardly by a springtensioning mechanism 470, which transmits force to the pressing tool 450through a tensioning drive axle 474. The pressing tool 450 transmitsthis downward force onto the ground coffee 438 as the tool 450 rotatesand incrementally and uniformly tamps the coffee into the deliveryfilter 414. The continual accumulation of compressed ground coffee 456underneath the pressing tool 450 applies upward pressure against thespring tensioning mechanism 470 and causes the pressing tool 450 to riseupwardly as the tool rotates. When the pressing tool 450 has movedupward a predetermined distance, a shut-off switch 478 of a portioningcontrol mechanism 480 is activated, completing the portioning processand ceasing the further introduction of ground coffee 438. The amount ofground coffee 438 that is compacted into the delivery filter 414 can bemodified using a volume portioning adjustment mechanism 484 whichchanges the activation position of the predetermined shut-off switch inthe portioning control mechanism 480.

The coffee bean storage container 420 is located in the upper right handcorner of the coffee roasting, grinding, portioning, and pressing device410. The storage container 420 generally acts as a funnel for channelingcoffee beans 422 to the coffee roasting device 421. The size and shapeof the storage container 420 can be altered in numerous ways withoutaffecting the functionality of the container 420 or departing from thescope of the present invention. The storage container 420 can hold asubstantial amount of raw coffee beans 422, so that frequent refillingof the device 410 is not required during extended periods of continuousor near-continuous coffee roasting, grinding and brewing production.Further, the storage container 420 is preferably configured so thatgravity alone is sufficient to direct the coffee beans 422 to theroasting device 421.

Raw coffee beans 422 enter the coffee roasting device 421 (configuredsimilarly to the roasting device shown and described in FIG. 7). Onceroasted, the roasted coffee beans are dispensed to the grinding mills424, where the coffee is finely ground and then discharged to the leftinto the ground coffee collection chamber 440. In one embodiment of thepresent invention all parallel and conical (flat) grinding mills 424(not shown, but known in the art) are utilized. In another embodiment,the grinding mills 424 employ two sets of grinding mills, one conicaland one parallel (also not shown). This combination of conical andparallel sets of mills produces a highly beneficial and consistentparticle grind uniformity for optimum release of flavor. Additionally,this combination of conical and parallel grinding mills 424 allows thedevice 410 to grind at a slow, uniform rate that helps preventover-heating of the mills which can damage the coffee and harm itsflavor. Further, grinding at this slower rate conserves energy andextends the burr life (period of time that the mill blades stay sharp)by a factor of three over traditional parallel mills.

As shown, the mill drive motor 430 is located in the lower right-handcorner of the coffee roasting, grinding, portioning, and pressing device410. The motor drive shaft 431 extends upward from the top of the milldrive motor 430. A mill shaft 432 extends parallel to the motor driveshaft 431 and downward from the bottom of the grinding mills 424. Themotor drive shaft 431 is connected to the mill shaft 432 by a mill drivebelt 433, thereby connecting the mill drive motor 430 to the grindingmills 424.

An internal fan 434 is also connected to the motor drive shaft 431, justabove the mill drive belt 433. The same motion created by the mill drivemotor 430 which powers the grinding mills 424 also powers the rotationof the internal fan 434, since the fan is connected to the motor driveshaft 431. The simultaneous activation of the internal fan 434 inconjunction with the use of the grinding mills 424, acts to cool andprevent overheating of the internal components contained in, andassociated with the grinding mills 424. The overheating of theseinternal components can result in damaging the flavor of the coffee andin the premature failure of the grinding mills 424 and associatedcomponents. The internal fan 434 draws in air from an inlet duct 436located directly above the fan.

After grinding, the ground coffee 438 is delivered into the groundcoffee collection chamber 440. The ground coffee collection chamber 440is frustoconical in shape, and tapers downward to the helical-shapedpressing tool 50 located in a bottom opening. Beneath the pressing tool450 is a detachable delivery filter 414, which is temporarily attachedto the device 410 by delivery filter attachment, mounts 464. Lining theinside of the delivery filter 414 is a filter container 66.

The pressing tool 450 undergoes a rotational motion when activated. Whenrotated, the helical shape of the pressing tool 450 provides a path forthe ground coffee 438 to pass through the pressing tool and into thedelivery filter 414. The helical-shaped pressing tool 450 includes tworamping fins.

The pressing tool drive motor 476 is located in the upper left-handcorner of the coffee grinding, portioning, and pressing device 410. Thedrive motor 476 is connected to the pressing tool 450 by a drive axle474, and is responsible for powering the rotational motion of thepressing tool 450. The helical configuration and rotational motion ofthe pressing tool 450 directs the ground coffee 438 through the pressingtool 50 and into the delivery filter 14. A spring tensioning mechanism470 is connected to the drive axle 474 and transmits a downward forceonto the pressing tool 450 through the drive axle 474. Specifically, thedrive axle 474 is slidably received with a rotor 471 that is locatedabove the spring mechanism 470. The upper end of the spring tensioningmechanism 470 attaches to the lower side of the rotor 471. The lower endof the spring tensioning mechanism 470 attaches to a concentric disc 472that in turn is affixed to the drive axle 474. In this manner, thespring tensioning mechanism 470 biases the drive axle 474, and thus thepressing tool 450 downward, via the attached concentric disc 472, whilealso allowing the rotation of the drive axle 474 by the drive motor 476to be compensated for by the rotor 471. Although in the preferredembodiment, a spring is used to provide the tensioning force in thetensioning mechanism 470, any number of known biasing mechanisms couldbe utilized therein.

An extended disc 475 is also connected to the drive shaft 474 above therotor 472. The disc 475 provides a substantially flat, circular surfacethat makes rolling contact with the roller shut-off switch 478 as theextended disc 475 is rotated by the drive motor 476, via the drive shaft474. The roller shut-off switch 478 activates when the switch has beenelevated a predetermined distance (by the extended disc 75).

The delivery filter 414 is temporary attached to the device 410 byplacing the filter over the depending pressing tool 450 and into matablecontact with the attachment mount 464. The delivery filter 414 is thenrotated 90 degrees locking the filter 414 into secured engagement withthe attachment mount 464. The filter 414 is then removed after beingfilled with a portioned and compacted amount of ground coffee 456, byrotating the filter 90 degrees in the opposite direction.

To produce roasted, ground, portioned, and compacted coffee using thisdevice 410, the operator places coffee beans 422 in the storagecontainer 420, attaches a portable delivery filter 414 to the attachmentmount 464, and turns on the machine 410. Turning on the machine 410activates the roasting device 421, grinding mills 24 and the rotatingpressing tool 50. The roasting device 421 roasts the raw beans 422,mills grinds the whole beans 422 into ground coffee 438, which isdirected into the collection chamber 440, the pressing tool 450 at thebottom the chamber 440 and into the delivery filter 414. The pressingtool 450 transmits downward force from the spring tensioning mechanism470 onto the ground coffee 438 in the delivery filter 414 as groundcoffee 438 passes underneath the rotating pressing tool 450. Thecombination of the helical configuration of the pressing tool 450, therotational motion of the pressing tool 450, and the downward force beingapplied onto the ground coffee 438 by the pressing tool 450,synergistically act together to incrementally and substantiallyuniformly tamp the ground coffee 438 into the collection filter 466within the delivery filter 414.

This uniform incremental tamping is produced by the helical pressingtool 50 using a single continuous rotational motion and substantiallyconstant downward force. In this manner, incremental tamping of thecoffee is performed as the collection filter 466 is filled from thebottom to the top, producing a compacted coffee “puck” 456 ofsubstantially uniform density. The continual incremental compactionproduced by the helical pressing tool 450 avoids the density gradientvariations typically found in coffee pucks produced using traditionaltamping techniques, which detract from optimal coffee flavor creation.Additionally, the density of the compacted coffee 456 produced by thisdevice can be modified by altering the strength of the spring or otherbiasing device utilized in the tensioning mechanism 470.

The roasting device 421 is positioned below a bean portioning device 486that selectively receives beans 422 from the container 420. The beanportioning device 486 is sized to receive a quantity of beans 422 fromthe container 420 sufficient for a single batch of roasted coffee beansfor one serving of coffee. The portion of beans 422 in the beanportioning device 486 are then deposited in the roasting chamber 423 ofthe bean roasting device 421. After roasting, the roasted beans 422′ arepassed through a chute 425 to the grinding mill 424.

The shaft 431 of the motor 430 is operably coupled to each of the fan434, roasting device 421 and portioning device 486. In a forwarddirection of rotation, the shaft 431 is rotated by the motor at arelatively high RPM, such as about 300 RPM to cause adequate air flowthrough the system by the fan 434 and to spin the mixing device 427 soas to rotate the beans 422 within the roasting chamber 423 during theroasting cycle. During the roasting stage, beans 422 are prevented fromentering the portioning device 486 or the roasting chamber 423. Afterroasting, the shaft 431 is rotated in an opposite direction, which maybe at a relatively slow RPM, such as about 60 RPM. Each interfacebetween the container 420 and the portioning device 486, between theportioning device 486 and the roasting device 421 and between theroasting device 421 and the grinding mill 424 includes a dispensingplate 429 that is operably controlled by the shaft via a clutchmechanism 431. The dispensing plate 429 is generally circular with anopening spanning approximately ⅓ of the plate. The bottom end plates 433of each of the container 420, portioning device 486 and roasting chamber423 include an opening also approximately equal to ⅓ of the end plate433. When the shaft 431 is spinning in a forward direction, eachdispensing plate 429 is positioned so that the dispensing plate coversthe opening of the respective bottom plate 433 and the shaft 431 isallowed to freely rotate relative to the end plates 433. In the oppositedirection, however, the clutch mechanism 431 causes the dispensing plate429 to rotate relative to the end plate 433 to align the opening in theend plate 433 with the opening in the dispensing plate 429 thus allowingbeans to move between respective components. By offsetting the relativeangular positions of the openings of the end plate 433 of eachcomponent, dispensing from the container 420 to the bean portioningdevice 486 can occur while the end plate 433 of the bean portioningdevice is closed. Likewise, after the beans are portioned in theportioning device 486, the plates between the container 420 and the beanportioning device 486 are closed and the plates between the beanportioning device 486 and the roasting chamber 423 are opened. Rotationof the shaft 431 in this position causes a dispensing bar 435 to pushthe beans into the opening. At this stage, the plates between theroasting chamber 423 and the grinding mill 424 are in a closed positionto prevent the raw beans from leaving the roasting chamber 423 untilafter the roasting stage is completed. Embodiments showing the openingand closing of the openings in the plates as described herein areillustrated in FIGS. 5 and 6. As such, a process for roasting, grindingand brewing coffee can be achieved with the device 410 according to thepresent invention.

It is further contemplated that water for brewing the coffee cold bedispensed through the roasting chamber and into the brewing portion ofthe machine. This would be beneficial in cleaning out the roastingchamber after each roast to remove oils and chaff produced duringroasting that may remain in the roasting chamber after each roast.Similarly, water from the espresso machine rinse cycle could be used toclean the roasting chamber.

In another embodiment, the coffee beans are roasted and espresso is madein a continuous process rather than in single servings. That is, coffeebeans are conveyed along a conveyor belt through a roasting device,through a grinding device and then to water extraction. Thus, each beanor at least as small cluster of beans proceeds through the process on amicro scale. A person can then make as small or large of an espresso asdesired. In addition, the process can be changed throughout the courseof making an espresso. For example, one could starting with a lightroast and slowing water extraction and then move to a heavy or darkerroast with a light water extraction.

Vending Machines

The systems, devices and methods of the present invention may also beutilized to provide coffee vending machines, for rapid, automated andconvenient dispensing of coffee at entertainment venues. For example,such automated vending machines may be configured to dispense aspecified quantity of coffee to a purchaser upon activation of apurchase transaction via a customer interface, which is used to initiatethe transaction by a purchaser. The purchase transaction may comprisepayment by coin, paper bill, a debit card or credit card, pre-paidcredit/debit card or gift card, internet banking service, token,near-field transmission card (radio frequency identification, or RFID),QR code, or the like. Thus, the device may include any suitable customerinterface capable of interacting with such payment methods. Suchcustomer interface may include, for example, a magnetic card reader, anear-field reader, a QR reader, or a keypad to manually enter creditcard information. The purchase transaction may comprise electronicpayment activated by a mobile device. Any suitable method for initiatingsuch a purchase transactions is contemplated herein. The machines may,for example, be connected to the Internet, either by wireless ortelephone cable signal, with encrypted transactions being activated bythe purchaser on demand, and dispensing of product upon receipt ofpayment.

The vending machines contemplated by the present invention will behighly efficient in dispensing coffee to purchasers as a result of therapid roasting and the unique physical properties of the resultingcoffee. The relatively small size of the devices disclosed herein areparticularly suitable for vending machines, which may be moved from onevenue to another, thus avoiding the need for dedicated machines thatremain at a venue permanently, even when no activities at the venue aretaking place.

The significantly increased roasting rates achieved through the devicesand methods of the present invention further expand the utility ofcoffee roasting machines in commercial, military and humanitarianapplications. For example, the high intensity microwave region roastingmachines can produce significantly larger quantities of coffee ondemand, within less than 20-30 seconds, such that it can keep up withcustomer demand at large entertainment venues, thereby increasing totalsales. Moreover, the relatively small size of the high intensitymicrowave region coffee roasting machines makes the machinessignificantly more portable, such that a single machine can be movedfrom one venue to another venue, thereby achieving a higher utilizationof a given machine.

The microwave roasting machines disclosed herein may be operated fromany suitable power source, include a standard electrical outlet.Portable machines may be powered either by standard electrical outletsavailable at the venue source, or may be operated by generator, battery,solar power, automotive power, or other available power supply. Batteryor solar powered devices may be useful, for example, when the device isused in remote locations where standard electrical power source isunavailable. It is understood by those skilled in the art that batteryor solar powered devices may require modifications to the electronicssystem that regulates operation of the device.

The vending machines disclosed herein may also comprise a high capacitystorage chamber, suitable for storing sufficient quantities of beans tobe dispensed during high demand or for large groups of individuals.Vending machines may also include, for example, metering devices forcontrolling the quantity of beans dispensed into the roasting chamber.

Methods

The improved system and method of making coffee heats coffee beans withmicrowave electromagnetic radiation by creating high intensity microwaveregions within a roasting chamber. The coffee beans are heated in thehigh intensity microwave regions until they roast to a desired andpreselected degree. As shown in FIG. 9, a method for roasting coffeebeans 500 according to the present invention includes the steps ofselecting a roast type 510, adjusting roasting time 520 according to thedesired roast type, powering the microwave emitter 530, detecting roastconditions 540 and dispensing the roasted beans 560 once roasting iscomplete 550.

For the selecting the roast type 510, the system of the presentinvention allows one to select a light roast 511, a medium roast 512 ora dark roast 513. Because of the ability to precisely control the roastproduced according to the present invention based on time of theroasting alone, it is contemplated that more precisely defined roastscan be selected, such as for example, a city roast, a full city roast, aFrench roast, a Spanish roast, etc.

For detecting roast conditions 540, various sensors may be incorporatedinto the system. For example, an optical sensor could be used todetermine bean color as an indication of the roast level. Likewise or inaddition to, an infrared sensor could be used to determine beantemperature as an indication of the roast level. Further, a sound sensorcould be used to determine time to first crack and time to second crackto more accurately determine the roast. Furthermore, by determining thetime to first crack and/or second crack, the roasting time can beadjusted based on the rate in which the beans are actually beingroasted. For example, roasting times can be affected by a variation inthe quantity of beans within the roasting chamber, the elevation atwhich the roasting is occurring, humidity in the ambient air, etc. Bydetecting roasting conditions in real time with one or more of thesensors herein described, the system 500 can adjust the roasting time520 to produce more accurate roasts based on the roast selected 510 bythe user.

In one aspect, the present invention also contemplates novel methods formaking coffee. In one embodiment shown in FIG. 10, a system 600 isprovided that comprises the steps of passing electromagnetic microwaveradiation through a roasting chamber 602 and maintaining at least oneantinode 604 of at least one microwave 606 at a substantially fixedlocation within the roasting chamber 602. The coffee beans 608 areheated with the microwave radiation at approximately the location of theone or more antinode 604.

In yet another aspect as shown in FIG. 11, the present inventionprovides a method for roasting coffee beans, comprising generating in asingle-mode resonant microwave applicator 610 a standing microwaveenergy field comprising an array of one or more anti-node high intensitymicrowave regions 612 and 614, and subjecting coffee beans 616 to themicrowave energy in the one or more high intensity microwave regions 612and 614, sufficient for the coffee beans to achieve a uniformdistribution of microwave energy heat to cause the coffee beans toroast. The roasting chamber 618 encompasses the one or more highintensity microwave regions 612 and 614. The coffee beans are moved, asindicated by the arrow through the microwave high intensity microwaveregions 612 and 614 within the roasting chamber 618 to achieve a highlyuniform distribution of microwave energy heat until roasted.

As shown in FIG. 12, the present invention provides a method forroasting coffee beans, comprising generating in a resonant microwaveapplicator 620 a standing microwave energy field comprising an array ofanti-node high intensity microwave regions 622-626, and subjectingcoffee beans 628 contained within one of a plurality of roasting chamber630 to the microwave energy in a respective high intensity microwaveregion 622-626, sufficient for the coffee beans to achieve a uniformdistribution of microwave energy heat to cause the coffee beans toroast. Each roasting chamber 630 is positioned at least partially withina respective one of the high intensity microwave regions 622-626. Thecoffee beans are moved through the microwave high intensity microwaveregions 622-626 within the roasting chamber 630 as herein described withrespect to other embodiments shown and described herein to achieve ahighly uniform distribution of microwave energy heat until roasted.

The methods and devices of the present invention are surprisinglyeffective in rapid and highly complete roasting of coffee beans. Indeed,it has been discovered that the above methods and devices producedcoffee produced coffee having unique and unexpected physical properties.While it has previously been believed by those of skill in the art thatroasting coffee too quickly or brewing coffee from freshly roasted beansis disadvantageous because of the amount of CO₂ still contained in thebeans, the coffee beans roasted in accordance with the principles of thepresent invention have achieved surprising results that appear to showsuperior and/or at least comparable crème while maintaining desired oilsfrom the beans in the brewed coffee, as compared to coffee brewed fromthe same coffee beans that have been roasted using traditional methods.In traditional coffee roasting techniques, the coffee beans are roastedfor a significantly longer period of time (e.g., 10-13 minutes) comparedto coffee beans that are roasted in accordance with the principles ofthe present invention (e.g., 30-40 seconds). As a result, oils from thecoffee beans roasted by traditional methods have time to seep from thecoffee beans That is, despite the retention of oil in the freshlyroasted beans of the present invention, which is the crème content andquality remains at least as high as that found when brewing coffee beansroasted by traditional methods.

Yet another surprising result was the discovery that coffee producedusing the methods and devices of the present invention resulted incoffee that was more completely roasted. Thus, the methods and devicesof the present invention improved roasting efficiency (i.e., thecompleteness of roasting of individual beans).

As previously discussed, green coffee beans can be completely roasted ina matter of seconds in accordance with the present invention. Thisallows for use of freshly roasted beans to make coffee once the beansare ground. For example, in preliminary testing using a roasting deviceof the present invention, 20 mL batches of green beans 20 mL of beanswere roasted for various times to produce roasts of varying degrees. Thefollowing table provides the results:

Time to 1^(st) Crack End Time Roast 18 30 Drying 17 35 Cinnamon 17 40New England 13 45 City 16 50 American 18 40 American 17 40 American

In these preliminary tests, a complete roast, such as a City or AmericanRoast, were achieved in as little as about 40 seconds. Improvements tothe roasting device of the present invention, however, have resulted inefficiencies that allow for a cinnamon roast in about 15 seconds and adark Spanish roast in about 30 seconds. For example, 20 mL of greencoffee beans were roasted with a roasting device according to thepresent invention with the following results:

Time to 1^(st) Crack End Time Roast 18 32 City 22 30 City 22 31 City 2030 American 18 29 American 19 28 American 20 26 New England 19 25Cinnamon/New Eng. 19 24 Cinnamon 18 33 Full City 20 34 Full City 20 32City

Starting with green coffee beans at room temperature (e.g., 72° F.), thedrying phase is reached at a bean temperature of 329° F., a CinnamonRoast is reached at a bean temperature of 385° F., a New England Roastis reached at a bean temperature of 401° F., an American Roast isreached at a bean temperature of 410° F., a City Roast is reached at abean temperature of 426° F., a Full City Roast is reached at a beantemperature of 437° F., a Vienna Roast is reached at a bean temperatureof 446° F., a French Roast is reached at a bean temperature of 464° F.,an Italian Roast is reached at a bean temperature of 473° F. and aSpanish Roast is reached at a bean temperature of 482° F. If the roastis allowed to progress beyond a Spanish Roast, the coffee will fullycarbonize and eventually combust. Thus, it is important for the coffeeroasting system of the present invention to be time and/or sensorcontrolled to prevent over-roasting of the coffee beans that couldresult in combustion. Moreover, it is important for the coffee roastingsystem of the present invention to be made of heat resistant materialsso as to prevent damage to the components of the coffee roasting systemas a result of the high bean temperatures during roasting. Based on thesize of the batch of green beans, the roasting times may vary slightlydue to the thermal load and other factors, such as elevation, humidity,ambient temperature, etc. However, consistent results have achieved fora full batch of beans of sufficient quantity for filling a typical portafilter with ground, roasted coffee beans with drying of the beans inabout 19 seconds, cinnamon roast in about 23 seconds, American roast inabout 26 seconds, full city roast in about 30 seconds, French roast inabout 34 seconds and Spanish roast in about 38 seconds.

Turning now specifically to the drawings, FIG. 1 shows a coffee roastingsystem 10. In order to roast coffee, beans are dispensed into a roastingchamber 18. This may be done from a storage container 66 through adispensing tube 68 and through an inlet 69. The coffee beans aresubjected to microwave energy emitted from an antenna 24 connected to amagnetron 22. The microwave energy is contained in a waveguide 28 toestablish a substantially standing wave so that the microwave energy hasnodes of minimal energy and anti-nodes of maximal energy. The roastingchamber 18 is disposed about the anti-node so that the coffee beansdisposed therein are exposed to high levels of focused microwave energy.

The focused microwave energy quickly heats the coffee bean and causes itto “crack.” In accordance with one aspect of the present invention, ithas been found that rapid heating of the bean can actually provideimprovements. By circulating the coffee beans in the roasting chamber,the beans revolve through the area within and around an anti-node, andmay be heated more uniformly within the individual beans and as a group.This, in turn, allows the coffee beans to roast to a greater degree.

The movement of the coffee beans in the roasting chamber 18 can beaccomplished by a variety of methods. These may include forced aircirculation, rotating the roasting chamber itself or using a stirringrod or other spinning device within the roasting chamber, which may beapparent in light of the present disclosure. As shown in FIG. 2, themovement of the coffee beans may be accomplished by a spinning cup. Asshown in FIG. 7, the movement of the coffee beans may be accomplished bya stirring device 324 within the cup 302. Alternatively, the movement ofthe coffee beans may be accomplished by a combination of a spinning cupand a stirring rod, with the stirring rod having one or more upwardlyextending arms adjacent the side wall of the cup to cause mixing of thebeans within the cup. In such an arrangement, the stirring rod may bestationary with the cup spinning around the stirring rod. Alternatively,the stirring rod may rotate in a direction opposite the spinning cup tocause the same tumbling effect of the beans within the cup while beingroasted to cause each of the beans to be subjected to substantially thesame average does of microwave energy during a roasting cycle. Also, aflow of air through the cup to circulate the beans within the cup may beprovided in addition to or alternatively to either the spinning cup orthe stirring rod as described herein. By directing the flow of airtangentially to the interior of the cup, a vortex of air is generatedwithin the cup to move the beans in a generally circular path within thecup.

It is also contemplated that heating elements may be disposed along theflow of air from the air source to preheat the air. It has been foundthat preheating the air can improve bean roasting, especially on theexterior of the bean. The heating element is advantageous as it providesadditional control over the heating gradient occurring with the coffeebeans. The microwave energy heats the water contained in the beans,while the heated air can be used to facilitate exterior roasting withina desired window of time.

The airflow can also be used to regulate humidity. For example, the airflow reduces residual moisture within the roasting chamber that maycause chaff from the roasted beans to stick to the sides of the chamber.The air flow through the roasting chamber reduces moisture deposits onthe walls of the roasting chamber and also can be used to carry thechaff out of the roasting chamber and collected by a filter or othercollection device

Turning to FIG. 13, there is shown a roasting chamber 718 and a waverepresenting focused microwave energy 720 as may be achieved from a waveguide 722. The microwave energy 720 has nodes 723 of minimal energy andanti-nodes 724 of maximal energy. At a frequency of 2.45 GHz, thewavelength is approximately 12.2 cm. Thus, the nodes 723 are spacedapart approximately 6.1 cm. Likewise, the anti-nodes 724 are spacedapart a similar distance. In order to contain the un-roasted beans 726in the area of the anti-node 724 and subject them to maximal energy, thecoffee beans are preferably contained in the area most closelysurrounding the anti-node 724. Thus, the diameter of the roastingchamber 718 may be less than one-half of the wavelength of the microwaveenergy, or alternatively about one-quarter of the wavelength, such asbetween about 2.5 and 3.1 cm (1 and 1.25 inches) for 2.45 GHz. As thebeans revolve and pass through the anti-node 724, the beans more evenlyheat.

The roasting chamber 718 is coupled to motor 730, which may be used torotate the chamber or to rotate a stirring device as previouslydescribed to move the beans 726 relative to the microwave energy field720. Both the motor 730 and the microwave emitter 732 draw power from anelectrical power source 734. In addition, the motor 730 and themicrowave emitter 732 are controlled by a controller 740. The controllerincludes a processor 742 for executing instructions in firmware orsoftware contained in memory 744 that control the length of time of theroast depending on user selection, or in the case of an espressomachine, to produce a proper roast for making espresso. The controller740 may also be in communication with one or more sensors 746 to detectroast status during the roast to more accurately produce a specificroast.

Referring again to FIG. 2, to prevent the un-roasted beans 12 fromescaping from the spinning cup 118, an annular lip 151 or a series ofprojections may be disposed adjacent the top of the spinning cup. Thelip 151 is preferably sized to contain un-roasted beans. Thus, forexample, the lip 151 may extend between about 1-10 mm. Unroasted beanswill run into and be held in the roasting chamber by the lip.

While discussed as being moved by airflow, a rotating mixing device anda spinning cup, it will be appreciated that other means exist forspinning the coffee within the roasting chamber so as to circulate thebeans about the anti-node. Such other means are intended to be coveredby the appended claims.

While FIG. 2 shows one embodiment of a microwave wave guide, which canbe used in accordance with the principles of the present invention, itwill be appreciated that other types of wave guides may be used. Forexample, an alternative microwave waveguide applicator for roastingcoffee beans may includes a magnetron, an antenna and a wave guide,which is generally circular, and a roasting chamber in which the coffeebeans may be disposed.

The devices of the present invention may also be configured with aportable power supply, such as a battery, solar power generator, orhookup for an automobile battery. The portable device may include, forexample, a customer interface operably connected to the electronicssystem that communicates with a payment source where funds are locatedfor payment of the product resulting from the device.

Thus, there are disclosed new apparatuses and methods for roastingcoffee. It will be appreciated that numerous modifications may be madewithout departing from the scope and spirit of the invention. Theappended claims cover such modifications to the devices and methodsclaimed below. In the foregoing specification, the present invention hasbeen described with reference to specific exemplary embodiments. Variousmodifications and changes may be made, however, without departing fromthe spirit and scope of the present invention as set forth in theclaims. The specification and figures are illustrative, not restrictive,and modifications are intended to be included within the scope of thepresent invention. Accordingly, the scope of the present inventionshould be determined by the claims and their legal equivalents ratherthan by merely the examples described.

For example, the steps recited in any method or process claims may beexecuted in any order and are not limited to the specific orderpresented in the claims. Additionally, the components and/or elementsrecited in any apparatus claims may be assembled or otherwiseoperationally configured in a variety of permutations and areaccordingly not limited to the specific configuration recited in theclaims.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to particular embodiments. Any benefit,advantage, solution to problem, or any element that may cause anyparticular benefit, advantage, or solution to occur or to become morepronounced are not to be construed as critical, required, or essentialfeatures or components of any or all the claims.

The terms “comprise”, “comprises”, “comprising”, “having”, “including”,“includes” or any variations of such terms, are intended to reference anon-exclusive inclusion, such that a process, method, article,composition or apparatus that comprises a list of elements does notinclude only those elements recited, but may also include other elementsnot expressly listed or inherent to such process, method, article,composition or apparatus. Other combinations and/or modifications of theabove-described structures, arrangements, applications, proportions,elements, materials, or components used in the practice of the presentinvention, in addition to those not specifically recited, may be variedor otherwise particularly adapted to specific environments,manufacturing specifications, design parameters, or other operatingrequirements without departing from the general principles of the same.

What is claimed is:
 1. An apparatus for roasting coffee beans,comprising: a roasting chamber for containing coffee beans; a microwaveemitter configured to produce microwave energy within the roastingchamber and heat the coffee beans to a temperature sufficient to roastthe coffee beans; a wave guide defining a resonant cavity configured togenerate a field of microwave energy comprising one or more stable highintensity microwave regions, the roasting chamber positioned at leastpartially within the wave guide at a location of the one or more stablehigh intensity microwave regions, wherein the one or more stable highintensity microwave regions includes a microwave energy maxima locatedat least partially within the roasting chamber; and a device configuredto move the coffee beans within the one or more high intensity microwaveregions.
 2. The apparatus of claim 1, wherein the device configured tomove coffee beans comprises a motor coupled to the roasting chamber torotate the roasting chamber relative to the wave guide.
 3. The apparatusof claim 1, wherein the device configured to move coffee beans comprisesa stirring device positioned within the roasting chamber, the stirringdevice coupled to a motor to rotate the stirring device relative to theroasting chamber.
 4. The apparatus of claim 1, wherein the deviceconfigured to move coffee beans comprises a blower in fluidcommunication with the roasting chamber for directing a flow of airthrough the roasting chamber during roasting of the coffee beans to movethe coffee beans in a generally circular path within the roastingchamber.
 5. The apparatus of claim 4, wherein the roasting chamberdefines one or more apertures that are sized to prevent coffee beansfrom passing through the one or more apertures, the flow of air passingthrough the one or more apertures.
 6. The apparatus of claim 4, furthercomprising a heating element in fluid communication with the flow of airto heat the air entering the roasting chamber.
 7. The apparatus of claim1, wherein the microwave emitter comprises an antenna at least partiallypositioned within the wave guide.
 8. The apparatus of claim 1, whereinthe roasting chamber comprises a cylindrical cup.
 9. The apparatus ofclaim 2, wherein the motor rotates the roasting chamber at about atleast 300 rpm.
 10. The apparatus of claim 3, wherein the motor rotatesthe stirring device at about at least 300 rpm.
 11. The apparatus ofclaim 1, wherein the wave guide comprises a rectangular tube formed by atop wall, a bottom wall, first and second side walls and first andsecond end walls, where an inside surface of the first end wall and aninside surface of the second end wall is spaced to produce a standingwave within the wave guide with a single microwave energy maxima locatedwithin the roasting chamber.
 12. The apparatus of claim 7, wherein thewaveguide defines a first aperture in a wall thereof for receiving theantenna of the microwave emitter there through and into the resonantcavity.
 13. The apparatus of claim 1, wherein the waveguide defines asecond aperture in a wall thereof and wherein the roasting chamberextends through the second aperture and into the resonant cavity. 14.The apparatus of claim 1, wherein the microwave emitter producesmicrowaves at 2.45 GHz.
 15. The apparatus of claim 1, wherein theroasting chamber is comprised of a material that is substantiallytransparent to microwave energy.
 16. The apparatus of claim 1, whereinthe field of microwave energy is sufficiently strong to roast the coffeebeans to a first crack or a second crack in less than one minute. 17.The apparatus of claim 1, further comprising a sensor for detecting aroast level of the coffee beans during roasting to adjust a roastingtime based on a sensor reading form the sensor.
 18. The apparatus ofclaim 17, wherein the sensor comprises at least one of a temperaturesensor, an infrared sensor, an optical sensor or a sound sensor.
 19. Anapparatus for roasting coffee beans, comprising: a microwave emitterconfigured to produce microwave energy; a single-mode resonant microwaveapplicator defining a resonant cavity and being coupled to the microwaveemitter to generate a standing microwave energy field comprising one ormore stable high intensity microwave regions within the resonant cavity,wherein the one or more stable high intensity microwave regions includesa microwave energy maxima; and a roasting chamber assembly positioned atleast partially within the resonant cavity, the roasting chamberassembly configured to contain coffee beans and to move the coffee beanswithin the one or more stable high intensity microwave regions, whereinthe microwave energy maxima of the one or more stable high intensitymicrowave regions is located at least partially within the roastingchamber.
 20. The apparatus of claim 19, wherein the roasting chamberassembly comprises a device configured to move coffee beans relative tothe microwave applicator.
 21. The apparatus of claim 20, wherein thedevice configured to move coffee beans comprises a motor coupled to theroasting chamber to rotate the roasting chamber relative to themicrowave applicator.
 22. The apparatus of claim 20, wherein the deviceconfigured to move coffee beans comprises a stirring device positionedwithin the roasting chamber, the stirring device coupled to a motor torotate the stirring device relative to the roasting chamber.
 23. Theapparatus of claim 19, wherein the device configured to move coffeebeans comprises a blower in fluid communication with the roastingchamber for directing a flow of air through the roasting chamber duringroasting of the coffee beans to move the coffee beans in a generallycircular path within the roasting chamber.
 24. The apparatus of claim23, wherein the roasting chamber defines one or more apertures that aresized to prevent coffee beans from passing through the plurality ofapertures, the flow of air passing through the one or more apertures.25. The apparatus of claim 23, further comprising a heating element influid communication with the flow of air to heat the air entering theroasting chamber.
 26. The apparatus of claim 19, wherein the microwaveemitter comprises an antenna at least partially positioned within themicrowave applicator.
 27. The apparatus of claim 19, wherein themicrowave applicator is formed from a waveguide material.
 28. Theapparatus of claim 19, wherein the roasting chamber comprises acylindrical cup.
 29. The apparatus of claim 21, wherein the motorrotates the roasting chamber at about at least 300 rpm.
 30. Theapparatus of claim 22, wherein the motor rotates the stirring device atleast about 300 rpm.
 31. The apparatus of claim 19, wherein themicrowave applicator comprises a rectangular tube formed by a top wall,a bottom wall, first and second side walls and first and second endwalls, where an inside surface of the first end wall and an insidesurface of the second end wall is spaced to produce a standing wavewithin the microwave applicator with a single microwave energy maximalocated within the roasting chamber.
 32. The apparatus of claim 26,wherein the microwave applicator defines a first aperture in a wallthereof for receiving the antenna of the microwave emitter there throughand into the resonant cavity.
 33. The apparatus of claim 19, wherein themicrowave applicator defines a second aperture in a wall thereof andwherein the roasting chamber extends through the second aperture andinto the resonant cavity.
 34. The apparatus of claim 19, wherein themicrowave emitter produces microwaves at 2.45 GHz.
 35. The apparatus ofclaim 19, further comprising a sensor for detecting a roast level of thecoffee beans during roasting to adjust a roasting time based on a sensorreading from the sensor.
 36. The apparatus of claim 35, wherein thesensor comprises at least one of a temperature sensor, an infraredsensor, an optical sensor or a sound sensor.